When the police see someone driving around breaking the law, it's their job to stop them.
But upholding laws on the road isn't a one-way street.
Gavin Seim turned the tables on a Washington state police officer in a video posted to YouTube last week, stopping the officer as the cop was driving an unmarked vehicle.
"Hey the reason I stopped you is I saw this car was unmarked," Seim asks the officer. "Is this a registered unmarked vehicle for undercover work?"
When the officer said it was a patrol car, Seim whipped out his legal knowledge.
"OK, you're not allowed to have patrol cars that are unmarked, are you aware of that?" he said, before citing the relevant law.
Washington state law allows police to use unmarked vehicles for special undercover work, but not for regular patrols.
Seim went through all the normal steps of a traffic stop, taking the officer's name, license and, eventually, deciding to let him off with a warning, urging him to speak with his bosses about their illegal patrol cars.
As Seim explained to the officer, using unmarked vehicles for regular patrols puts citizens in danger, because people can never be sure if they're really being pulled over by cops or not.
"In Washington we have unmarked police vehicles impersonating citizens," he wrote in a blog post on the topic. "If you think it’s not a serious issue, try asking those that have been raped or lost loves ones because of unmarked cars."
Watch the encounter here:
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