This is backwards. This is really backwards.
Last week, "Liberty Speaker" Gav Seim posted a video of himself pulling over an unmarked patrol car. In the video (embedded below), the activist lectures the visibly annoyed sheriff's deputy on the illegality of unmarked police cars, asks to see his identification, tells him that he could be arrested for going on patrol in an unmarked car, and eventually lets him off with a warning.
It'd be hilarious if the activist wasn't so smug (anyone who says, "We the people are sentinels of our liberty" can't be taken too seriously). But more importantly, does he have a point?