concurring:

I concur in the result reached by the majority. Because I believe Officers Hornberg and McCluskey are entitled to qualified immunity, I agree that we should affirm the district court’s grant of summary judgment to these defendants. However, the majority opinion goes beyond what is necessary for qualified immunity analysis, concluding that Officers Hornberg and McCluskey did not violate Orin’s First Amendment rights because they had probable cause to arrest him for trespass and failure to disperse. In my view, these additional conclusions are unnecessary and unwarranted. Because the qualified immunity question is sufficient to dispose of the case against Officers Horn-berg and McCluskey, our analysis need not go further. Moreover, I cannot agree with the majority’s conclusion that the officers had probable cause to arrest Orin.

Probable cause to arrest without a warrant exists when the facts and circumstances known to the arresting officer are sufficient to lead a prudent person to believe the suspect has committed, is committing, or is about to commit a crime. Mackinney v. Nielsen, 69 F.3d 1002, 1005 (9th Cir.1995). Viewing the facts in the light most favorable to Orin, as we must on summary judgment, no prudent person would have thought Orin was doing anything illegal. To the contrary, the record suggests that Orin was arrested because the police and campus security were afraid that observers of the protest were getting violent and would harm the protesters. The majority cites no authority, and I am aware of none, that indicates the hostile reaction of an audience to a speaker creates probable cause to arrest that speaker.

Under Washington law, the elements of failure to disperse are 1) “congregating] with a group of three or more other persons [when] there are acts of conduct within that group which create a substantial risk of causing injury,” and 2) “failing] to disperse when ordered to do so by a peace officer.” Wash. Rev.Code § 9A.84.020(1) (2001) (emphasis added). However, there were only two other members of Orin’s group, so the police could not have observed Orin congregating with “three or more persons.” More importantly, viewing the facts in Orin’s favor, neither he nor members of his group were engaging in conduct that created a substantial risk of injury. 1 Even if members of the crowd *1220 were engaging in such conduct, that did not create probable cause to arrest Orin for failure to disperse.

A person is guilty of trespass if “he knowingly enters or remains unlawfully in or upon premises of another.” Wash. Rev. Code § 9A.52.080(1) (2001). If the property in question is a public place, however, a person’s presence there is not unlawful as long as the person has complied with “all lawful conditions imposed on access to or remaining in the premises.” Id. § 9A.52.090(1); State v. Finley, 97 Wash.App. 129 , 982 P.2d 681, 686 (1999); State v. R.H., 86 Wash.App. 807 , 939 P.2d 217, 219-220 (1997). In other words, if the premises are open to the public, violating a lawful condition of access is a necessary element of criminal trespass under Washington law. See R.H., 939 P.2d at 220 .

In the present case, Orin provided evidence that the protesters were complying with the lawful, content-neutral conditions imposed by Dean Barclay. The campus security officers admitted that the protesters complied when asked to move away from entrances to buildings. Officer Hornberg, in his deposition, did not mention seeing Orin blocking access to buildings or otherwise violating Dean Barclay’s lawful conditions. Upon arriving on campus, Officer Hornberg observed the protesters standing with their backs against a planter box, and feared violence on the part of a crowd encircling the protesters, not violence by the protesters themselves. Thus, the only information available to Hornberg that indicated Orin might be breaking the law was Wallace’s statement that the protesters were violating conditions imposed on them by Dean Barclay. Before Orin was arrested, however, Orin specifically told Hornberg that Barclay and Wallace wanted the protesters to leave only because they were talking about religion. This undermined Hornberg’s reason for believing Orin was trespassing, and should have put him on notice that Orin was not violating any lawful conditions placed on access to the campus. Under these circumstances, I cannot agree with the majority’s conclusion that there was probable cause to arrest Orin for trespass.

In performing their jobs, police officers must often make split-second judgments in dangerous situations. Qualified immunity recognizes that they sometimes make mistakes, and protects them from liability when their mistakes are reasonable. See, e.g., Saucier v. Katz, 533 U.S. 194 , 121 S.Ct. 2151 , 2158, 150 L.Ed.2d 272 (2001). Because I believe Officers Hornberg and McCluskey were mistaken, but reasonably so, I agree they are entitled to summary judgment. I cannot join the majority opinion, however, to the extent it concludes that the hostile reaction of an audience to a speaker creates probable cause to arrest that speaker. In my view, “the proper response to potential and actual violence is ... to arrest those who actually engage in such conduct, rather than to suppress legitimate First Amendment conduct as a prophylactic measure.” Collins v. Jordan, 110 F.3d 1363, 1372 (9th Cir.1996).

. There was evidence that one of the protesters, McIntyre, swung at a campus security officer, knocking the officer's hat off his head. However, McIntyre claimed this was an acci *1220 dent. At any rate, viewing the facts in Orin’s favor, this incident does not amount to conduct on the part of the protesters that would create a "substantial risk of injury.”