Cops try to do that shit all the time. Sounds like a real douchebag. The key is, though, to have one story and stick to it, no matter what.

One time I got pulled over and the cop said something like "son this car smells like a hash factory." and he also said "Son, you're TOASTED."

Luckily I had no herb on me.

The cops asked me about a hundred times "Where's the pot? We know you were smoking, you might as well stop lying." But no matter what, I said "I have no pot, and I wasn't smoking any."

I'm telling you, if you have a good story and you stick to it, cops can't fuck with you. They think they can play mind games cause you're stoned. Well i was fuckin ripped that day (it was april 20 a couple years ago) and the cops didnt find shit, so they let me go.

Also, on a side note, if you've been drinking and you get pulled over, NEVER EVER EVER take a breathalizer test. EVER.