This case comes to us following an order of a single justice of this court vacating a preliminary injunction issued against the defendants. The injunction required the defendants, various unincorporated associations and individuals, to refrain from trespassing on, or obstructing access to, *703offices or clinics of the plaintiffs at which abortion, counseling, and family planning services are provided. For the reasons stated, we order that the injunction be reinstated.3
We note the following facts drawn from the record before the motion judge in the Superior Court at the time the injunction was issued. On April 19, 1989, the plaintiffs brought a class action on behalf of themselves and those who might seek to obtain services at the plaintiffs’ clinics (clinics). The plaintiffs charged the defendants with eight counts of illegal activity arising out of protests at the clinics, including violations of the Massachusetts Civil Rights Act, intentional infliction of emotional distress, intentional interference with prospective contractual relations, invasion of privacy, false imprisonment, trespass, nuisance, and conspiracy. The plaintiffs’ verified complaint sought immediate injunctive relief to “prevent defendants and those acting in concert with them from . . . blockading] family planning clinics in Massachusetts and threaten[ing], intimidating] and coerc[ing] the clinics’ patients and staff.”
In support of their request for a preliminary injunction, the plaintiffs submitted the affidavits of fourteen eyewitnesses to protests at the clinics, newspaper articles describing these protests, local police arrest records of the days when protests were held, informational literature published by the organizational defendants regarding such protests, and several other documents. The plaintiffs’ complaint stated that the purpose of the organizational defendants was to “organize and coordinate blockades and disruptions of abortion and family planning facilities,” and alleged that a majority of the individual defendants had been “arrested at least twice in Massachusetts in conjunction with [his or her] anti-abortion blockades and activities.” Police records from the Brookline and Worcester police departments showed that all the indi*704vidual defendants had been arrested at least twice on dates corresponding to protests held at the clinics.
The protests were described in the affidavits, signed by affiants who claimed to be eyewitnesses to the events described. These affiants' stated that the defendants blocked entranceways and lobbies of the clinics by lying on the ground, thereby preventing patients and staff from entering or leaving the clinic. At one protest, one defendant named in the complaint chained herself to a clinic door with a bicycle lock, and, at another protest, one demonstrator chained himself to a toilet in a clinic. Local police attempted to clear the entranceways but were not always successful. As the police moved people away from the entranceways, other protesters would move to fill the vacancy. Protesters who had been removed by the police often would return to their original positions upon their release. The defendants also sang and chanted during the protests and engaged in “sidewalk counseling” in an effort to dissuade people from attempting to enter the clinics. Similar descriptions of protest activity appeared in the newspaper articles submitted by the plaintiffs. One eyewitness stated that she was unable to obtain an abortion on the day for which she had been scheduled, due to the protests.
The organizational defendants’ literature refers to the protests as “rescues,” which are described as attempts to shut down clinics “by peacefully, but physically blockading abortion [clinics] with [protesters’] bodies” (emphasis in original). A newsletter published by one organizational defendant provides the following description of a protest at a Massachusetts clinic: “Sending about 75 rescuers as a decoy to [one clinic] . . . , [the protesters] were able to draw the police away from the entrance to [another clinic]. When the entrance was clear, about 40 rescuers who had waited nearby simply walked in and took up their positions. Another 200, including those who had allowed themselves to be dragged from the [first clinic’s] entrance, joined the rescue, blocking the outside doors.”
*705In response to the plaintiffs’ complaint, thirty-nine of the sixty-nine defendants filed answers prior to the issuance of the injunction. These defendants declined to respond to specific allegations of blocking clinic entranceways or trespassing on clinic property, invoking their rights under the Fifth Amendment to the United States Constitution and art. 12 of the Massachusetts Declaration of Rights.4 Several other defendants filed affidavits in opposition to the motion for injunctive relief. One such affidavit stated that the goal of “Operation Rescue: Boston” was to “stop abortion by nonviolent direct action such as sidewalk counselling, picketing and rescues.” Another affidavit, in describing the protests, stated: “We use our bodies in the only way possible in this struggle. We lay upon the ground at which time it is the decision of the authorities to remove us or not by whatever means they chose [sic].”
On July 24, 1989, after a hearing and consideration of the arguments of counsel and the affidavits and memoranda filed in the case, the judge granted the plaintiffs’ motion for a preliminary injunction.5 Forty of the sixty-nine defendants petitioned a single justice of the Appeals Court, seeking relief from the injunction pursuant to G. L. c. 231, § 118, first par. *706(1988 ed.). A single justice in the Appeals Court denied the petition. These same defendants then brought a petition for relief before a single justice of this court (single justice) under G. L. c. 211, § 3 (1988 ed.). On August 16, 1989, the single justice suspended the preliminary injunction “until the final disposition of this case or until further order of this court.” The plaintiffs then moved the single justice to report his decision to the full court. This motion was denied on August 22, 1989. At the time of oral argument before this court, the case had not yet come to trial.
The plaintiffs currently appeal the decision of the single justice to the full court and also directly petition the full court for relief pursuant to G. L. c. 211, § 3. For the purposes of this case, the plaintiffs’ appeal and their c. 211, § 3, petition to the full court have been consolidated, and, hence, we treat them as a single action.
1. Availability of G. L. c. 211, § 3 Review.
General Laws c. 211, § 3, confers on this court the power of “general superintendence of all courts of inferior jurisdiction to correct and prevent errors and abuses therein if no other remedy is expressly provided.” This discretionary power of review has been recognized as “extraordinary,” and will be exercised only in “the most exceptional circumstances.” Costarelli v. Commonwealth, 374 Mass. 677, 679 (1978). We will not allow resort to c. 211, § 3, “merely as a substitute for normal appellate review.” Francis v. District Attorney for the Plymouth Dist., 388 Mass. 1009, 1010 (1983), quoting Soja v. T.P. Sampson Co., 373 Mass. 630, 631 (1977). Parties seeking review under c. 211, § 3, must “demonstrate both a substantial claim of violation of [their] substantive rights and error that cannot be remedied under the ordinary review process.” Dunbrack v. Commonwealth, 398 Mass. 502, 504 (1986). Parents of Two Minors v. Bristol Div. of the Juvenile Court Dep’t, 397 Mass. 846, 849 (1986). The plaintiffs’ petition to this court satisfies both of the requirements of this exacting test.
First, the plaintiffs allege that the defendants are engaged in a systematic attempt to deprive women of the opportunity *707to obtain abortion, counseling, or family planning services. At the very least, the right to choose to terminate a pregnancy by abortion has been recognized as a substantive right under both the Federal and State Constitutions. Roe v. Wade, 410 U.S. 113 (1973). Moe v. Secretary of Admin. & Fin., 382 Mass. 629 (1981).6 In support of their claims, the plaintiffs have produced voluminous documentary evidence and eyewitness affidavits describing the defendants’ obstruction of clinics which provide abortion services, and alleging at least one instance in which a woman could not obtain an abortion due to the defendants’ protests. The defendants, in their brief to this court, have made no attempt to deny the specific allegation that they sought, by way of their protests, to obstruct the clinics so that no abortions could be performed. In light of the record below, we conclude that the plaintiffs have demonstrated “a substantial claim of violation of [their] substantive [rights].” Dunbrack v. Commonwealth, supra at 504.
The plaintiffs have also shown that, absent relief under c. 211, § 3, they may suffer an “error that cannot be remedied under the ordinary review process.” Id. at 504. This requirement derives from that portion of c. 211, § 3, which allows relief only “if no other remedy is expressly provided.” This court has repeatedly interpreted this language to require that no other effective remedy be available to the petitioners. Doe v. Doe, 399 Mass. 1006, 1007 (1987). Parents of Two Minors, supra at 849. Commonwealth v. Dunigan, 384 Mass. 1, 5 (1981). A party lacks an effective remedy if the available methods of review would be unable to place him in “statu quo.” Elder v. Commonwealth, 385 Mass. 128, 132 *708(1982), quoting Costarelli, supra at 680. Commonwealth v. Dunigan, supra at 5, quoting Gilday v. Commonwealth, 360 Mass. 170, 171 (1971).
We have allowed review under c. 211, § 3, in cases where alternate appellate procedures were available to the petitioning party. In Costarelli v. Commonwealth, supra, we used our superintendence powers to review a claim of a violation of the right against double jeopardy, despite the availability of an appeal following a new trial. We noted that “[the] guaranty against being twice exposed to the risk of conviction, regardless of whether conviction actually results, would be seriously weakened if appellate review of a claim of double jeopardy were delayed until after a second trial.” Id. at 680. See Elder v. Commonwealth, supra at 132. Similarly, in Doe v. Doe, supra, we upheld the exercise of c. 211, § 3, review to resolve a child custody dispute, even though there was an alternate appellate remedy available. In reaching our decision, we observed that the alternate appellate process might involve delay, and that “[custodial] [circumstances may change rapidly, and the harm sought to be avoided [by the custody proceeding] may worsen with the passage of time.” Id. at 1007. We allowed c. 211, § 3, review because the alternate appellate process might not be able to place the petitioning party in statu quo, due to the possible delay. Id. See Parents of Two Minors, supra; Custody of a Minor (No. 2), 386 Mass. 460 (1982).
These cases illustrate the principle that certain substantive rights may not survive the delays inherent in the normal appellate process. In certain circumstances, the practical effect may be that these rights are lost during the process of appeal and review to which a party ordinarily must turn for protection. The dilemma posed by such a situation presents an appropriate case for c. 211, § 3, review.
In the present case, the plaintiffs retain the obvious option of proceeding to a trial on the merits of their claim for permanent injunctive relief. However, even if the plaintiffs were to be successful at trial, there would be an inevitable delay between the present and the point at which the trial judge *709would grant relief from the defendants’ alleged obstruction of clinics. For example, the right to obtain an abortion is time-sensitive, and “effectively expires in a matter of weeks from the onset of pregnancy.” Bellotti v. Baird, 443 U.S. 622, 642 (1979). Therefore, the option of a trial on the merits may be insufficient to place in statu quo those women who may be successful in obtaining permanent injunctive relief from the defendants, but whose right to obtain an abortion will be lost due to the passage of time. We conclude that, in the unique circumstances of this case, the plaintiffs are entitled to relief under c. 211, § 3.
The standard for deciding the question whether a preliminary injunction was properly issued, when the question comes before a single justice of this court under G. L. c. 211, § 3, after G. L. c. 231, § 118, first par., consideration by a single justice of the Appeals Court, is the traditional, i.e., Packaging Indus. Group v. Cheney, 380 Mass. 609 (1980), standard. This is also the standard on review of a trial judge’s order by a single justice of the Appeals Court under G. L. c. 231, § 118, and by a three-judge panel of that court on appeal from such a single justice. A litigant should not be permitted to avoid application of the Packaging Indus. Group standard by opting to seek relief under G. L. c. 211, § 3, instead of appealing to a panel of the Appeals Court under the second paragraph of § 118 (and seeking a stay pending appeal or an expedited decision). Thus, we apply the same standard in reviewing the decision of the single justice of this court vacating the preliminary injunction.7
*7102. The Preliminary Injunction.
The standard under which a request for a preliminary injunction is considered appears in Packaging Indus. Group v. Cheney, 380 Mass. 609 (1980). This standard requires that, through “an abbreviated presentation of the facts and the law ... the moving party must show that, without the requested relief, it may suffer a loss of rights that cannot be vindicated should it prevail after a full hearing on the merits.” Id. at 616. At the same time, the party opposing the injunction may make a similar showing of irremediable harm which would occur were the injunction to issue. Id. The task for the motion judge is to balance the risk of irreparable harm to the plaintiff and defendant “in light of [each] party’s chance of success on the merits” at trial. Id. at 617. “Only where the balance between these risks cuts in favor of the moving party may a preliminary injunction properly issue.” Id.
The judge in the present case found that the plaintiffs risked irreparable harm and enjoyed a probability of success on the merits. After balancing “the interests involved,” the judge granted the plaintiffs’ request for a preliminary injunction. As we review these findings, we keep in mind that, “[i]n reviewing the granting ... of a preliminary injunction, the standard is whether the [trial] court abused its discretion. An appellate court’s role is to decide whether the [trial] court applied proper legal standards and whether there was reasonable support for its evaluation of factual questions.” Id. at 615, quoting Hochstadt v. Worcester Found, for Experimental Biology, 545 F.2d 222, 229 (1st Cir. 1976). See Foreign Auto Import, Inc. v. Renault Northeast, Inc., 367 Mass. 464, 472 (1975). In considering the plaintiffs’ c. 211, § 3, petition, we apply the same standard of review.
The plaintiffs requested an injunction in order to protect their right to give and to obtain abortion and family planning services. As we noted earlier, the time-sensitive nature of this right can transform a temporary delay of its exercise into a complete denial of the right. Therefore, the judge’s finding that the plaintiffs risked irreparable harm finds strong sup*711port in the record. Regarding the plaintiffs’ likelihood of success on the merits, we have already concluded, in our earlier discussion, that the plaintiffs have established a “substantial” claim of a violation of their right to obtain an abortion. While we have no record of what transpired at the hearing on the plaintiffs’ motion for a preliminary injunction, the documentary record presented by the plaintiffs is replete with alleged instances of illegal activity on the part of the defendants, including trespass on clinic property and obstruction of clinic entranceways.8 The plaintiffs presented evidence that the defendants had blockaded their clinics, effectively preventing the provision of abortion and family planning services, and that the defendants routinely ignored police orders to clear the clinics’ entrances. The plaintiffs presented eyewitness accounts, newspaper articles, arrest records,9 and the *712defendants’ own organizational literature in support of their motion.
In response to the plaintiffs’ charges, the defendants filed answers to the complaint and affidavits in opposition to the motion for a preliminary injunction.10 Neither of the affidavits denied the plaintiffs’ specific allegations. In fact, one affidavit admitted that “[w]e lay upon the ground at which time it is the decision of the authorities to remove us or not.” The answers filed by the defendants denied the paragraphs of the plaintiffs’ complaint which contained the eight counts of illegal activity, but did not deny the plaintiffs’ specific allegations describing illegal activity occurring during protests at the clinics. Instead, in response to those paragraphs, most of the defendants chose to invoke their right to decline to answer in order to avoid possible self-incrimination.11 One defendant admitted, in her answer, that she and other protesters had blocked a clinic doorway and had gone limp when police arrived to remove her.
The defendants’ answers presented affirmative defenses to the plaintiffs’ complaint, but the record reveals no suggestion of any supporting facts presented by the defendants. For example, the defendants did not present any evidence to sug*713gest that they were not present at the protests, or that they had been given permission to demonstrate on clinic property. “Evidence that goes beyond the unverified allegations of the pleadings and motion papers must be presented to support or oppose a motion for a preliminary injunction.” Brookline v. Goldstein, 388 Mass. 443, 450 n.10 (1983), quoting 11 C.A. Wright & A.R. Miller, Federal Practice and Procedure § 2949, at 469 (1973). Given the plaintiffs’ extensive presentation of facts to support their complaint and the defendants’ failure affirmatively to oppose those facts,'we conclude that the judge acted within her discretion in finding that the plaintiffs enjoyed a likelihood of success on the merits of their complaint.12
Furthermore, the defendants failed to demonstrate that they would suffer a risk of irreparable harm if the injunction were issued. While the defendants did present to the judge a defense that their actions described in the complaint were protected by the First Amendment to the United States Constitution, the defendants’ concern that an injunction might interfere with their rights under the First Amendment does not by itself constitute a sufficient showing of a risk of irreparable harm for the purposes of a preliminary injunction.
When issuing an injunction, a judge must differentiate between legal and illegal expressive activity, and must carefully tailor the injunction to avoid unconstitutionally infringing on activity protected by the First Amendment. See NAACP v. Claiborne Hardware Co., 458 U.S. 886, 907-915 (1982). Clearly, some of the defendants’ activities at the protests, *714such as singing and chanting on public sidewalks, are protected, expressive activity. However, for the purposes of demonstrating a risk of irreparable harm, the defendants are not entitled to assume that the judge will issue an injunction which deprives them of their right to free expression. The acceptance of such an assumption would allow a showing of a risk of irreparable harm to be made on no more than a subjective lack of confidence in the abilities of the judge who is to issue the injunction. In light of the extensive record provided by the plaintiffs and the limited response of the defendants, the risk of irreparable harm shown by the plaintiffs and the failure of the defendants to demonstrate a similar risk, we conclude that the judge acted within her discretion in issuing the preliminary injunction.
3. First Amendment Issues.
The defendants claim that the injunction is unconstitutionally vague and overbroad, in violation of the First Amendment, and that it constitutes an impermissible prior restraint oh their right to freedom of expression guaranteed by the First Amendment. Specifically, the defendants point to that portion of the injunction which prohibits “obstructing” access to the clinics. The defendants contend that an injunction which prohibits “obstruction” could be construed to prohibit constitutionally protected activity as well as illegal activity. We are not persuaded by this argument.
A statute, or injunction, will be considered unconstitutionally vague if it “either forbids or requires the doing of an act in terms so vague that men of common intelligence must necessarily guess at its meaning and differ as to its application.” Connally v. General Constr. Co., 269 U.S. 385, 391 (1926). The purpose of the vagueness doctrine is to ensure that all “be informed as to what the state commands or forbids.” Smith v. Goguen, 415 U.S. 566, 574 (1974), quoting Lanzetta v. New Jersey, 306 U.S. 451, 453 (1939). In this manner, people have an opportunity to guide their conduct in conformity with the law, and those entrusted with the enforcement of the laws are provided with strict guidelines for their application. Groyned v. Rockford, 408 U.S. 104, 108 *715(1972). The prohibition against overly vague laws protects people from having voluntarily to curtail activities which, although protected by the First Amendment, may be confused with illegal activity due to an unconstitutionally vague statute. Id. at 109.
In the present case, we are not persuaded that use of the word “obstructing” strips the injunction of its coherence to persons of common intelligence. The vagueness of a particular statute or injunction should be considered with reference to the factual situation to which it applies. Id. at 112. In the context of this injunction, given the history of prior protests, and the pending litigation between the plaintiffs and the defendants, the phrase “obstructing access” can only be construed as referring to the physical blocking of access to the clinics, either by demonstrators sitting or lying in entranceways to prevent patients or staff from entering the clinics, or by the use of inanimate objects to achieve the same purpose. We are in agreement with the United States Court of Appeals for the Ninth Circuit which, when presented with an injunction which prohibited “obstructing the free and direct passage of any person in or out of [a clinic],” held that “[t]he terms of the injunction place the enjoined parties on fair notice of the actions that are prohibited in language that is reasonably understandable.” Portland Feminist Women’s Health Center v. Advocates for Life, Inc., 859 F.2d 681, 684-685 (9th Cir. 1988). The injunction is not unconstitutionally vague.
The injunction also survives the defendants’ overbreadth challenge. “A clear and precise enactment may ... be ‘over-broad’ if in its reach it prohibits constitutionally protected conduct.” Grayned v. Rockford, supra at 114. The defendants claim that the injunction is overbroad in that it prohibits the privileged exercise of First Amendment rights. However, the injunction does no more than enjoin the defendants from engaging in illegal activity, such as trespass or obstruction of clinic entranceways, in their efforts to have their message heard. The injunction does not prohibit other types of expressive activity, such as praying, singing, or peaceful picketing, *716which does not unduly interfere with the rights of others. There is no First Amendment right to “cordon off . . . [an] entrance to a public or private building” in an effort to exercise the right to free expression. Cox v. Louisiana, 379 U.S. 536, 555 (1965). The right to free speech “[does] not disable the government from taking reasonable steps to ensure that [this right is] not exercised in a manner which infringes on the legitimate rights of other citizens.” Brookline v. Goldstein, 388 Mass. 443, 450 (1983). The injunction prohibits only that conduct which, although expressive, is not protected by the First Amendment. Therefore, it is not overbroad.
Finally, the defendants claim that the injunction constitutes a prior restraint on the free exercise of their First Amendment right to free expression. It is true that the injunction imposes certain restrictions on expressive activities prior to their anticipated occurrence at future protests. However, the prospective nature of the injunction does not render it an impermissible prior restraint. The government may impose reasonable restrictions which have prospective effect on the time, place, and manner of expressive conduct if such regulations can be shown to further a “sufficiently important governmental interest in regulating the [conduct which justifies] incidental limitations on First Amendment freedoms.” Texas v. Johnson, 109 S. Ct. 2533, 2540 (1989), quoting United States v. O’Brien. 391 U.S. 367, 376 (1968). This “governmental interest” must be “unconnected” to suppression of the content of the expression at issue in order to justify the regulation. Texas v. Johnson, supra at 2541.
In the present case, we have no doubt that the State’s interest in utilizing a preliminary injunction to protect its citizens, residents, and visitors from irreparable harm constitutés a “sufficiently important governmental interest.” See Portland Feminist Women’s Health Center v. Advocates for Life, Inc., supra at 686. Also, the injunction is content-neutral, and makes no reference to the specific viewpoints espoused by the defendants or the plaintiffs. The injunction leaves the defendants free to express their views through any *717number of alternate methods not prohibited by the injunction, such as singing, lecturing, or peaceful picketing. Clearly, the governmental interest in enforcing the injunction relates to the prevention of illegal activity, and not to “the suppression of [the defendants’] expression.” Texas v. Johnson, supra at 2541. We conclude that the State’s interest in imposing the injunction justifies the minimal limitations placed on the defendants’ expressive activity.
4. Conclusion.
The injunction issued in this case represents a proper exercise of the discretion accorded to judges to provide appropriate interlocutory relief. We concur with the single justice of the Appeals Court that the preliminary injunction is “narrow, carefully tailored, and reasonably specific”, and “does not . . . threaten the defendants’ First Amendment rights.” Accordingly, the suspension of the injunction is vacated, and the injunction is reinstated until the final disposition of this case or until further order of this court.
So ordered.
We acknowledge with appreciation the assistance of amici American Jewish Congress, the Attorney General, and the Civil Liberties Union of Massachusetts.
The record is unclear as to the exact number of defendants who invoked their Fifth Amendment and art. 12 rights when answering the plaintiffs’ complaint. The plaintiffs point to at least thirty-nine defendants who invoked these rights, and the defendants do not contest this allegation.
The preliminary injunction order states:
“After hearing, and after consideration of arguments of counsel and review of the affidavits and memoranda filed, the Court, finding irreparable harm and probability of success on the merits, and balancing the interests involved, hereby ORDERS that the above-named defendants, all of whom have been served, and their agents, servants, employees and those acting in concert with them are preliminarily enjoined from:
“a. trespassing on, blocking, or in any way obstructing access (either ingress or egress) to the offices or clinics of plaintiff providers of services, and
“b. physically restraining or obstructing or committing any acts of force or violence against persons entering, leaving, working at or seeking to obtain services from plaintiff providers,
until further order of the Court.”
The defendants’ claim that what is at issue in the present case is the plaintiffs’ ability to obtain a preliminary injunction. They argue that there is no personal substantive right to obtain an injunction and therefore suggest that the test for c. 211, § 3, review has not been met. This argument ignores the fact that the preliminary injunction in the present case was sought in an attempt to safeguard the right to obtain an abortion, which is a personal substantive right. The defendants do not appear to dispute the plaintiffs’ standing to assert such a right.
The plaintiffs’ petition requests that we review the order of the single justice. Ordinarily, in response to such a petition, “[tjhe inquiry of the full court will be whether the single justice has abused his discretion.” Commonwealth v. Dunigan, 384 Mass. 1, 5 (1981). Commonwealth v. Yelle, 390 Mass. 678, 685, n.5 (1984). To facilitate this determination, this court previously has exercised its power of review under c. 211, § 3, to examine the merits of the case presented to the trial judge. See, e.g., Parents of Two Minors v. Bristol Div. of the Juvenile Court Dep’t, 397 Mass. 846, 851 (1986); Commonwealth v. Dunigan, supra at 6; Commonwealth v. Cook, 380 Mass. 314, 321-322 (1980). Accordingly, we turn to the merits of the controversy.
For example, an eyewitness affiant, Jamie Ann Sabino, identified one defendant, William Cotter, as a leader of a group of protesters who attempted to block the opening of a passageway to a clinic formed by a line of police officers. William Cotter was also identified by eyewitness affiant Leslie Loveless as one of a group of ten protesters who initiated a blockade of a clinic by standing in front of the clinic’s entrance. In addition, the answer of another defendant, Harriet Fremont-Smith, admitted that she participated in “sit-ins” at the plaintiffs’ clinics, while the affidavit of a third defendant, Constance Smith, the executive director of Operation Rescue: Boston, stated that “[w]e lay upon the ground at which time it is the decision of the authorities to remove us or not by whatever means they chose [sic]."
The defendants argue that arrest records are “incompetent” evidence and cannot support a finding of likelihood of success on the merits. This argument fails to appreciate that a hearing on a motion for preliminary injunction is not a trial on the merits, and that we have allowed evidence to be considered in such a hearing even though it might later prove inadmissible at trial. Brookline v. Goldstein, 388 Mass. 443, 450 n. 10 (1983). The possible inadmissibility of evidence can be taken into account by the judge in according proper weight to the evidence, but does not prevent the judge from considering the evidence. Id. at 450. “[Ijnasmuch as the grant of a preliminary injunction is discretionary, the trial court should be allowed to give even inadmissible evidence some weight when it is thought appropriate to do so in order to serve the primary purpose of preventing irreparable harm before a trial can be had.” 3 C.A. Wright & A.R. Miller, Federal Practice and Procedure § 2949, at 471 (1973 ed. & 1989 Supp.). Given the danger of irreparable harm in the present case, the *712judge could properly consider the arrest records, even though they might subsequently prove inadmissible at trial.
In their brief to this court, the defendants claim that the organizational defendants were not properly served prior to the hearing on the plaintiffs’ motion for a preliminary injunction. See Mass. R. Civ. P. 23.2, 365 Mass. 769 (1974). We do not address this claim because the defendants specifically waived all issues of service of process and notice during oral argument before this court.
“[A]n adverse inference drawn from the failure of a party to testify [on the ground of self-incrimination] is not sufficient, by itself, to meet an opponent’s burden of proof.” Custody of Two Minors, 396 Mass. 610, 616 (1986). However, if “a case adverse to the interests of the party affected is presented so that failure of a party to testify would be a fair subject of comment,” such an inference may be taken into account. Id. In the present case, the plaintiffs have presented a sufficient case adverse to the interests of the defendants, through eyewitness affidavits, arrest records, and other documents, to allow the judge to draw an inference from the defendants’ invocation of their Fifth Amendment and art. 12 rights.
The defendants claim that the injunction could not have been issued under the count of the plaintiffs’ complaint which alleges a violation of the Massachusetts Civil Rights Act. They argue that, regardless of the likelihood of plaintiffs’ success on the merits of their civil rights claim, the injunction does not meet the requirements of G. L. c. 12, § 11J (1988 ed.), for injunctions issued pursuant to civil rights statutes. While this may be true, the record also supports a finding that the plaintiffs enjoy a likelihood of success on the merits of their trespass claim. The trial judge reasonably could have concluded that potential future acts of trespass, resulting in the blockade of clinics, might irreparably harm the plaintiffs and those people they represent in this case.