I'd swear that this case was a made-up law school hypothetical if I hadn't actually read it in the advance sheets myself.
I won't tell you how it comes out. Though I will tell you that the district court and the Ninth Circuit disagreed regarding the proper result.
The issue presented is whether the seizure described below was permissible. As for the relevant facts, the first two substantive paragraphs of the opinion say it all:
"Ascension Alverez-Tejeda and his girlfriend drove up to a traffic light. As the light turned green, the car in front of them lurched forward, then stalled. Alverez-Tejeda managed to stop in time, but the truck behind him tapped his bumper. As Alverez-Tejeda got out to inspect the damage, two officers pulled up in a police cruiser and arrested the truck driver for drunk driving. The officers got Alverez-Tejeda and his girlfriend to drive to a nearby parking lot, leave the keys in the car and get into the cruiser for processing. Just then, out of nowhere, someone snuck into their car and drove off with it. As the couple stood by in shock, the police jumped into their cruiser and chased after the car thief with sirens blaring. The police then returned to the parking lot, told the couple that the thief had gotten away and dropped them off at a local hotel.
The whole incident was staged. DEA agents learned that one of the leaders of a drug conspiracy was dealing drugs out of his car and deduced from several intercepted calls and direct surveillance that Alverez-Tejeda, one of the conspiracy’s subordinates, was using the leader’s car to transport illicit drugs. The agents decided to stage an accident/theft/chase in order to seize the drugs without tipping off the conspirators. Every character in the incident, other than Alverez-Tejeda and his girlfriend, was either a DEA agent or a cooperating police officer."