A few days I mentioned how an auditor team showed up dressed as firemen to do an inspection at a bank branch. They totally buffaloed everyone in the branch as the loaded spyware and such.

A cop stopping you on the side of the road in a full cop car is a little different.

But if they were ever to show up at your facility also ask to see their id. They will be carrying that too. That gives you more reassurance. And if you've never seen them before, you can always call the department with the id in hand and they'll confirm it.