dissenting.
The majority holds that no search occurred when defendant’s employer used a radio transmitter to secretly monitor her movements during the work day. Unless government employees have no constitutionally protected right against electronic surveillance in the workplace, the form of surveillance that the government employed here cannot be distinguished from the form of surveillance that the court held unconstitutional in State v. Campbell, 306 Or 157, 759 P2d 1040 (1988). Because I would hold that government employees retain a right to privacy against this form of surveillance, I respectfully dissent.
Defendant worked for the United States Forest Service (USFS). The record does not disclose that the USFS had *532any reason to suspect that defendant was either violating its workplace rules or engaging in criminal activity. USFS special agents, however, attached a radio transmitter to defendant’s truck so that they could secretly monitor her movements during the work day. Using the transmitter, the federal agents tracked defendant’s movements throughout the day and discovered evidence of arson. On appeal, defendant argues that attaching the transmitter to her work truck constituted a search for the purposes of Article I, section 9, of the Oregon Constitution. It follows, she reasons, that the evidence that ,Le federal agents obtained cannot be used against her in a state criminal trial unless they either had a warrant or an exception to the warrant requirement applies.
If the federal government had prosecuted defendant in federal court, the evidence that the agents obtained as a result of the radio transmitter would have been admissible. The Fourth Amendment does not prohibit the government from attaching a radio transmitter to any person’s car and tracking that person’s movements on public roads. See United States v. Knotts, 460 US 276, 281, 103 S Ct 1081, 75 L Ed 2d 55 (1983). As the Court explained in Knotts, a radio transmitter merely permits police officers to discover what is open to public view. Id. at 281-83. Because a transmitter’s use does not invade a person’s privacy interests under the Fourth Amendment, using a transmitter to monitor a person’s movements on public roads does not constitute a search for the purposes of the federal constitution. Id. at 285.
The state, however, chose to prosecute defendant in state court, and the Oregon Supreme Court has reached a different conclusion under Article I, section 9, of the Oregon Constitution. See Campbell, 306 Or at 172-73.1 In Campbell, the court explained that using a hidden radio transmitter to monitor a person’s movement on public roads is no different from using a hidden listening device to monitor that person’s conversation. Id. at 172. Each is a search because it permits the government to surreptitiously monitor public actions *533that a person reasonably understood were private. Id. The court reasoned in Campbell:
“The problem presented by this case is essentially much like that presented in Katz [v. United States, 389 US 347, 353, 88 S Ct 507, 19 L Ed 2d 576 (1967)], which was whether using a hidden listening device placed in a public place could be considered a search. Conversations in public may be overheard, but it is relatively easy to avoid eavesdroppers by lowering the voice or moving away. Moreover, one can be reasonably sure of whether one will be overheard. But if the state’s position in this case is correct, no movement, no location and no conversation in a ‘public place’ would in any measure be secure from the prying of the government. There would in addition be no ready means for individuals to ascertain when they were being scrutinized and when they were not. That is nothing short of a staggering limitation upon personal freedom. We could not be faithful to the principles underlying Article I, section 9, and conclude that such forms of surveillance were not searches.”
Id. at 172. The court accordingly held that “the use of the radio transmitter to locate [the] defendant’s automobile was a search under Article I, section 9, of the Oregon Constitution.” Id.
The majority’s holding in this case — that the use of a radio transmitter to surreptitiously monitor defendant’s movements did not constitute a search — cannot be squared with the court’s holding in Campbell, unless defendant’s status as a government employee somehow changes the analysis. The majority identifies essentially two reasons why defendant’s employment bears on that question. It notes initially that defendant’s employer consented to attaching the transmitter to the government truck that defendant drove at work. It reasons that, “[u]nlike in Campbell, there was no physical invasion or trespass of defendant’s property interests.” 184 Or App at 528. Although the federal agents did not trespass on defendant’s property interests, it does not follow that they did not invade her privacy interests.
If the absence of a trespass were dispositive, government employers could surreptitiously bug an employee’s office phone, place a hidden microphone in an employee’s *534office, or secretly put a camera in the company bathroom. The fact that no trespass occurs because the employer owns the office phone or the building where the employee works does not divest an employee of any privacy interest in the workplace. Rather, as the majority implicitly acknowledges and as the courts have uniformly recognized since Katz, a person does not lack a constitutionally protected privacy interest merely because the government’s efforts to discover what a person says or does do not constitute a trespass. Katz, 389 US at 351-52; Campbell, 306 Or at 168-69. Were the rule otherwise, Katz would have been decided differently.
The majority advances an alternative rationale. It reasons that defendant’s “employer was entitled to know where its vehicle was at all times during the work day.” 184 Or App at 530. The majority’s reasoning proves too much. An employer is surely entitled to know what its employees do during the work day. For example, an employer is entitled to know whether its employees are using the office phones and computer equipment for work-related or personal reasons. But it does not follow that government employers may place a hidden bug in the office phones or surreptitiously monitor an employee’s use of e-mail. Government employees do not give up their constitutional rights when they accept public employment. Rather, as the Oregon Supreme Court has recognized, government employees retain their right to be free from unreasonable searches and seizures in the workplace. See AFSCME Local 2623 v. Dept. of Corrections, 315 Or 74, 843 P2d 409 (1992) (Article I, section 9); cf. State v. Beugli, 126 Or App 290, 297, 868 P2d 766, rev den, 320 Or 131 (1994) (Article I, section 12).
To be sure, the operational realities of the workplace may limit the scope of an employee’s privacy rights. See O’Connor v. Ortega, 480 US 709, 717-18, 107 S Ct 1492, 94 L Ed 2d 714 (1987) (plurality opinion). And the fact that a government employer tells its employees in advance that it will be monitoring their use of the office computers or phones can be an important factor in the analysis. See Wayne R. LaFave, 4 Search and Seizure: A Treatise on the Fourth Amendment § 10.3(d), 486 (3d ed 1996). But there was no advance notice *535here,2 and the operational realities of the workplace do not permit government employers to surreptitiously bug their employees’ office phones or install hidden cameras in their offices to observe their activities during the day. Requiring citizens to go through the day wondering whether their conversations and actions are subject to electronic surveillance is inconsistent with the principles that underlie Article I, section 9. Campbell, 306 Or at 172-73. That is so whether they are government employees or not.
Neither reason the majority advances for distinguishing Campbell suffices. Indeed, even the majority does not suggest that Article I, section 9, permits government employers to engage in every form of surreptitious monitoring. Its holding appears to rest ultimately on the proposition that using a radio transmitter to track defendant’s movements during the day did not invade any privacy interest that she had because her location on a public highway or public lands was not truly private. 184 Or App at 530-31. In effect, the majority embraces the United States Supreme Court’s reasoning in Knotts. Whatever the merit of that reasoning, the Oregon Supreme Court expressly rejected it in Campbell. 306 Or at 166-67. We are not free to revive it. Beyond that, in Campbell, the court specifically equated using a radio transmitter to monitor a person’s movements with using a hidden microphone to listen to a person’s conversation. Id. at 172. In light of that equation, we cannot hold that government employers are free to surreptitiously attach radio transmitters to their employees’ work vehicles unless we are also willing to say that they may secretly bug their office phones. Following Campbell, I would hold that the USFS’s actions constituted a search.
Because the government’s actions constituted a search for the purposes of Article I, section 9, the remaining question is whether the search was justified. The USFS did not obtain a warrant before attaching the radio transmitter *536to defendant’s work truck, but the state argues that its actions fell within one of the exceptions to the warrant requirement. It argues that the USFS’s consent was sufficient to justify its actions.3 If, however, defendant has a right of privacy against USFS’s placing a monitoring device on her work truck, allowing the USFS to consent to that act would vitiate that privacy right. See United States v. Taketa, 923 F2d 665, 673 (9th Cir 1991).4 Because the USFS’s actions constituted a search for which there is no justification, I respectfully dissent.
Judges Armstrong, Wollheim, and Brewer join in this dissent.
Even though the federal agents obtained the evidence consistently with the federal constitution, the evidence is not admissible in a state criminal prosecution unless the evidence was also obtained consistently with the state constitution. State v. Davis, 313 Or 246, 254, 834 P2d 1008 (1992).
This case accordingly does not require us to decide whether Article I, section 9, would prevent a government employer from monitoring its employees’ movements or communications if it gave them advance notice of its actions. See Wayne R. LaFave, 4 Search and Seizure: A Treatise on the Fourth Amendment § 10.3(d), 486 (3d ed 1996); United States v. Simons, 206 F3d 392 (4th Cir 2000). Rather, this case involves only surreptitious monitoring.
Analytically, the USFS’s consent is relevant in two related but separate respects. First, because the USFS consented to attaching the transmitter to its truck, there was no trespass. The majority reasons that the absence of a trespass bears on the question whether the agents violated defendant’s privacy interests and thus engaged in a search. As explained above, the fact that the government did not interfere with defendant’s property interests does not mean that its action did not invade her privacy interests. Second, consent is also an exception to the warrant requirement. The state argues that, even if there was a search, the USFS’s consent is sufficient to justify the invasion of defendant’s privacy interests. Because I would hold that attaching the radio transmitter was a search, it is necessary to reach the state’s argument.
In Taketa, one of the defendants was an officer of the local bureau of investigations who was working with the Drug Enforcement Agency (DEA). The DEA eventually began investigating him and another DEA agent for suspicion of illegal wiretapping. Part of their investigation involved the DEA’s searching the defendant’s office. The defendant was convicted and, on appeal, argued that the search of his office violated the Fourth Amendment. The government attempted to justify its actions by arguing that the head of the DEA could consent to the search on behalf of the defendant. The Ninth Circuit held tfyt “allowing such employer ‘consent’ would destroy the expectations of privacy ir- vhe workplace we have recognized as valid.” 923 F2d at 673.