This is an appeal from an order denying appellants’, Coatesville Development Company and Giant Food Stores, petition for a preliminary injunction against appellees, two locals of the United Food and Commercial Workers Union. We affirm.
On August 28, 1984, appellant Giant Food Stores, Inc. (Giant) opened a new supermarket at Thorndale Shopping Center which shopping center is owned1 by Coatesville Development Company (Coatesville). The Thorndale Shopping Center consists of several stores in addition to Giant and a large parking area, and it is immediately adjacent to another shopping center which includes a competitor of Giant. The same day that the store opened, appellees were engaged in a labor dispute with Giant and began picketing and distributing handbills in front of the store as well as in the parking lot of the shopping center. The appellees charged that Giant paid substandard wages to its employees and discouraged public patronage of the store. The Union was not attempting to organize Giant’s employees and none of the pickets was employed by Giant.
Coatesville has no policy limiting or restricting the purposes for which a person is invited onto the mall premises. *334Giant has a policy prohibiting unauthorized solicitation by non-employees on its premises and prohibiting employees from soliciting during working time on both the company’s property as well as in the common areas of the shopping center. This policy is made known to the public by a sign which is posted inside the store’s vestibule. The sign reads:
UNAUTHORIZED SOLICITATION FOR ANY PURPOSE OR THE DISTRIBUTION OF LITERATURE OF ANY KIND BY NON-EMPLOYEES ON COMPANY PREMISES IS NOT PERMITTED.
EMPLOYEES ARE NOT PERMITTED TO SOLICIT OR DISTRIBUTE LITERATURE DURING WORKING TIME IN WORKING AND PUBLIC AREAS.
The sign is not visible to one driving past the store in an automobile, and there is no positive evidence in the record that the sign is visible by pedestrians in the parking lot or on the sidewalk outside the store.
The day after the picketing began, Giant obtained a temporary ex parte injunction permitting the pickets, but limiting their number and their location, at specific places on the sidewalk and in the parking areas of the mall. Five days later, Giant and the Union consented to the entry of an injunction on terms similar to the ex parte injunction, and the trial court made the consensual injunction an order of court. However, both the Union and Giant expressly reserved the right to assert and challenge, respectively, the Union’s legal right to picket on the mall property.
Almost three months after the ex parte injunction was obtained, Coatesville filed a separate complaint in equity against the Union seeking a temporary and permanent injunction against all picketing on its property by the Union. Despite Giant’s consent to the earlier limited injunction in its separate action, Giant, along with Coatesville, filed an amended complaint in Coatesville’s equity action naming both Coatesville and Giant as plaintiffs in the action. One of the paragraphs in the complaint stated that all the proceedings in Giant’s separate action in which it had consented to the preliminary injunction were incorporated by *335reference. In its answer to the amended complaint, the Union denied that anything from Giant’s separate action against the Union was incorporated or that the two actions had been properly joined. Also, in response to the amended complaint the Union filed unfair labor charges against appellants. The National Labor Relations Board dismissed the charges on the basis that the Union had failed to show that appellants’ action was frivolous or lacking a reasonable basis in fact or in law, or that the action was retaliatory. Thus, it did not constitute an unfair labor practice.
In December, 1984, a hearing was held in the Coatesville/Giant action on the issue of whether the trial court should grant the requested preliminary injunction and permit the Union to picket on appellants’ property. The trial court determined that while peaceful picketing on private property is not protected by the First Amendment of the United States Constitution, it is protected by Art. 1, § 72 of the Pennsylvania Constitution.
In reaching its conclusion, the trial court relied on Commonwealth v. Tate, 495 Pa. 158, 432 A.2d 1382 (1981), in which our Supreme Court held that the Pennsylvania Constitution affords more expansive protection of free speech than the federal constitution. Tate further established a test which balances the right to possess and use property against the right of free expression. Applying this test to the instant action, the trial court held that it was a reasonable exercise of police power to permit peaceful picketing *336by the Union on appellants’ property particularly since it determined that the Union’s alternatives were wholly inadequate. Thus although the trial court found that the Pennsylvania Constitution protected the Union’s right to picket, it found it unnecessary to grant the preliminary injunction because the existing injunction granted in Giant’s separate action against the Union and which was agreed to by Giant and the Union but not Coatesville, was an appropriate accommodation of the parties’ constitutionally protected rights. For these reasons the trial court denied the petition for a preliminary injunction in the present case.
Coatesville and Giant appealed from the order denying the preliminary injunction claiming that the trial court erred in holding that the Union’s right to picket and distribute handbills on private property was constitutionally protected. A panel of this Court reversed the trial court’s order by holding that the Union did not have a right under the Pennsylvania Constitution to picket on the private property of Coatesville and Giant.
Reargument before the court en banc was granted, and the parties were given permission to file supplemental briefs addressing the impact of the recent decision of the Pennsylvania Supreme Court in Western Pennsylvania Socialist Workers v. Connecticut General Life Insurance Co., 512 Pa. 33, 515 A.2d 1331 (1986). The trial court had addressed the Superior Court’s disposition of Socialist Workers, 335 Pa.Super. 493, 485 A.2d 1 (1984), which had held that a privately owned shopping center was purely private and, therefore, the state constitution did not restrict the owner’s right to prohibit political activity on its property. However, the trial court found that the Superior Court had relied on a line of cases rejected by the majority in Tate and that it had misconstrued Tate.
Despite the emphasis on the constitutional rights of the parties in the trial court’s opinion, the panel’s disposition, and the parties’ briefs, we find it unnecessary to reach the constitutional issue of whether Article 1 § 7 of the Pennsylvania Constitution protects the right of union mem*337bers engaged in a labor dispute with a store to picket and distribute, on the private property of a shopping center, including the parking lot and sidewalks of the shopping center, handbills announcing that the store does not comply with area-standards with regard to its treatment of employees. We can determine whether the trial court’s order denying the preliminary injunction was an abuse of discretion by applying principles of the common law. Where an issue can be resolved on a basis other than constitutional law, the court should not address the constitutional question. Ballou v. State Ethics Commission, 496 Pa. 127, 436 A.2d 186 (1981). We therefore will not address the constitutional issue.
Before discussing the merits of the case we note that despite the cessation of Union picketing at Giant’s store at the Thorndale Shopping Center in April, 1985, the present case involves an exception to the strict application of the doctrine of mootness. The Union is still picketing at other Giant stores, and because the Union can stop picketing at any time, it is quite possible that the issue involved here would not reach the appellate courts before the Union would stop picketing. Therefore, this case presents an important issue which is likely to escape review. Consequently, we will not apply the doctrine of mootness, but will reach the merits of the case. See Western Pennsylvania Socialist Workers v. Connecticut General Like Insurance Company, 512 Pa. 23, 515 A.2d 1331 (1986); Wiest v. Mt. Lebanon School District, 457 Pa. 166, 320 A.2d 362, cert. denied, 419 U.S. 967, 95 S.Ct. 231, 42 L.Ed.2d 183 (1974).
The standard of review of an order denying or granting a preliminary injunction is well established.
As a preliminary consideration, we recognize that on an appeal from the grant or denial of a preliminary injunction, we do not inquire into the merits of the controversy, but only examine the record to determine if there were any apparently reasonable grounds for the action of the court below. Only if it is plain that no grounds exist to support the decree or that the rule of law relied upon was *338misapplied will we interfere with the decision of the Chancellor. Intraworld Inc. v. Girard Trust Bank, 461 Pa. 343, 336 A.2d 316 (1975); Credit Alliance Corporation v. Philadelphia Minit-Man Car Wash Corp., 450 Pa. 367, 301 A.2d 816 (1973); Zebra v. Pittsburgh School District, 449 Pa. 432, 296 A.2d 748 (1972). “In order to sustain a preliminary injunction, the plaintiffs right to relief must be clear, the need for relief must be immediate, and the injury must be irreparable if the injunction is not granted.” Zebra v. Pittsburgh School District, 449 Pa. at 437, 296 A.2d at 750 (emphasis added). Roberts v. School District of Scranton, 462 Pa. 464, 469, 341 A.2d 475, 478 (1975) (emphasis added).
Willman v. Children’s Hospital of Pittsburgh, 505 Pa. 263, 269, 479 A.2d 452, 454-455 (1984). We can affirm the decision of a trial court on any basis even if the reasons givén by the trial court for its decision are incorrect. Commonwealth v. Allem, 367 Pa.Super. 173, 532 A.2d 845 (1987). Applying this limited scope of review, we affirm.
Grounds for the trial court’s order denying a preliminary injunction in this case exist. Most importantly, it was proper not to grant an injunction in this case because neither Coatesville nor Giant took adequate measures to prohibit the activities of the Union. The property involved here, a shopping center, undeniably was open to the public for the public to come onto the property despite the fact that it was privately owned. Coatesville placed no limitations whatsoever on the conduct which could be engaged in upon that property. While Giant attempted to limit the scope of activities on its property, the extent of those limitations is not clear.
Giant’s posted notice concerning non-solicitation and distribution of handbills was located only inside the store and was not visible from outside the store. Yet the activity to which Coatesville and Giant object, is activity conducted outside the store. For Giant’s efforts to prohibit the picketing and handbilling engaged in on the parking lot and on the sidewalk to be effective, its prohibition must be clear *339and unambiguous, and it must state unequivocally the nature of the conduct prohibited and the location to which the prohibition extends. Furthermore, Giant’s prohibition on the particular activity must exist prior to the commencement of the activity and cannot be imposed ex post facto.
Giant’s alleged no-solicitation policy satisfied none of these requirements. The notice which was posted did not unequivocally state that picketing could not be conducted on the property. The words on the sign posted inside the store stated only that there could be no solicitation and no distribution of handbills. It did not prohibit people wearing or carrying placards from walking and standing on the property. Therefore, at least some of the activities of the Union were not expressly prohibited.
Giant’s notice also did not unambiguously indicate the geographic parameters of its no-solicitation rule. As to non-employees, the sign simply stated that solicitation and distribution were prohibited “on company property.” The public, which is not privy to the precise language included in Giant’s lease with Coatesville, would have no idea precisely what constituted “company property,” and the public certainly could not be expected to understand “company property” to relate to common areas of the shopping center including the parking lot and sidewalks, even if the agreement between Coatesville and Giant provided that such areas were to be considered Giant’s company property. Furthermore, the sign setting forth the prohibition was located inside the store and could not be seen from outside the store. Thus, at the time that the Union began to picket on the sidewalks and in the parking lot, neither Giant nor Coatesville can be said to have taken measures to unambiguously and specifically have prohibited the activity of the Union nor taken measures to ensure that the Union, picketing outside the store only, would have known about the policy.
This case is factually distinguishable from Socialist Workers, where a plurality of the Supreme Court upheld a trial court’s refusal to enjoin the owners of a shopping mall *340from enforcing their non-solicitation policy. Although we do not have the benefit of all the information concerning the shopping mail’s non-solicitation rule in Socialist Workers, what we do know about it distinguishes it from the present case. In Socialist Workers, the shopping mall required a permit to solicit in the common areas. When the political organizers applied for a permit, it was denied because the mall had a uniform policy denying all political solicitation on its property. In the present case, there was no general permit requirement for solicitation, and there was nothing to indicate a clear and unambiguous, uniformly applicable policy as in Socialist Workers. We therefore, do not find the ultimate result in Socialist Workers to be applicable here.
Neither the right of the Union to picket nor the right of the Coatesville and Giant to limit the conduct permitted on its private property is absolute. However, in the absence of any unambiguous and meaningful prohibition on the use of the shopping center property, we cannot conclude that under the common law the trial court erred in allowing the union to continue its activities on the property until the rights of the parties were finally determined. We hold that the trial court properly denied the preliminary injunction in this case because where a private property owner holds his property open for public use and invites the public onto the property, the property owner is not entitled to an injunction against peaceful informational picketing directed at the conduct of one of the possessors of the property or a tenant on the property in the absence of an established policy specifically and unambiguously prohibiting such picketing on the property in the specific location where the picketing is being conducted and in the absence of a publication of the policy prohibiting such activity where those conducting the prohibited activity can reasonably be expected to be aware of the publication of the policy.
Furthermore, we note that the injunction which was denied here was only a preliminary one and not a permanent one. The rights of the parties to the use of this property *341has not yet been finally determined. Moreover, the trial court was aware that a limited preliminary injunction had already been obtained. In light of our limited scope of review and the fact that the record supports the trial court’s decision, we affirm the trial court’s order denying the preliminary injunction.
Order affirmed.
BECK, J., files a concurring opinion. TAMILIA, J., files a concurring and dissenting opinion.. Technically, Coatesville Development Company does not have full legal and equitable title to the shopping center. Coatesville has entered into a land installment sales agreement to purchase the shopping center, and as a result of that agreement, it has equitable title to the shopping center.
. Article 1 § 7 of the Pennsylvania Constitution provides:
The printing press shall be free to every person who may undertake to examine the proceedings of the Legislature or any branch of government, and no law shall ever be made to restrain the right thereof. The free communication of thoughts and opinions is one of the invaluable rights of man, and every citizen may freely speak, write and print on any subject, being responsible for the abuse of that liberty. No conviction shall be had in any prosecution for the publication of papers relating to the official conduct of officers or men in public capacity, or to any other matter proper for public investigation or information, where the fact that such publication was not maliciously or negligently made shall be established to the satisfaction of the jury; and in all indictments for libels the jury shall have the right to determine the law and the facts, under the direction of the court, as in other cases.