Issue: Whether the police may search, incident to the arrest of the driver, a passenger’s personal belongings (in this instance: an eyeglass case) found outside the vehicle.
¶56 The record indicates that Officer Hahn was concerned about the possible threat posed by Denk as well. In a situation where two men were alone in a car permeated with the smell of burning marijuana, it is reasonable for an officer to be concerned that Denk could attempt to assist Pickering, either by endangering the officer or by concealing evidence of his friend’s crime. 
¶57 Officer Hahn’s suspicions were further aroused when he arrived at the passenger side of the car. There, he noticed a hard, opaque container large enough to conceal a small weapon or further evidence related to the possession or distribution of narcotics. The eyeglass case was positioned on the ground, just underneath the car and accessible from the passenger seat. The very presence of the container on the ground, in that spot, was suspicious.
¶61 We determine that the warrantless search here was incident to the arrest and was supported by both of the historical rationales at the heart of that exception, namely the safety of the arresting officer and the need to discover and preserve evidence. In this situation, Office Hahn was outnumbered at a late night arrest involving two men and knew that narcotics were present. The proximity of the eyeglass case to the car, to Denk, and to Pickering, as well as its unexplained location at Denk’s feet, raised questions about the danger Denk posed acting alone or in concert with Pickering. Thus, we conclude that based on the reasoning in State v. Pallone, the search of the eyeglass case was a permissible search incident to the arrest of the driver of the vehicle.
¶62 Lest our discussion be misconstrued, we reiterate the bright-line rule that unarrested passengers cannot themselves be searched based solely on the arrest of the driver.  In order to search the body of a passenger, the arresting officer must have individualized cause to justify the search. For example, “protective frisks are justified when an officer has a reasonable suspicion that a suspect may be armed. The reasonable suspicion must be based upon specific and articulable facts, which, taken together with any rational inferences that may be drawn from those facts, must establish that the intrusion was reasonable.” State v. McGill, 2000 WI 38, ¶22, 234 Wis. 2d 560, 609 N.W.2d 795 (citations and quotations omitted).
In a sense, the court’s expression is backward: it’s not so much that there is a bright-line rule, but that there isn’t: to uphold the search of a passenger incident to arrest of the driver, the police must have “individualized cause,” determined case-by-case same as a Terry-type frisk. And such cause was abundant, the car exuding the smell of marijuana, ¶9, among other things. Although the court doesn’t go so far as to say (and it’s certainly not clear the particular facts would have supported the result), at least in some instances the odor of burning marijuana may itself justify PC-based search of a passenger, State v. Mitchell, 167 Wis. 2d 672, 482 N.W.2d 364 (1992). In any event, the odor alone certainly providedprobable cause to search the car—and, under Pallone, passenger property within it. Of course, in this instance the property was found outside the car, but the court links it closely to the car, ¶¶51-52, and thus this distinction becomes in effect a mere detail. But none of this background should obscure the idea that search of passenger property must be supported by individualized cause, whether found inside or out of the car. (Is something like “reasonable suspicion” required? The court doesn’t quite say, but arguably so.)