...I like finding things I've forgotten about, but....I'd be kind'a pissed to find a bud in my car, until I smoked it.
...let's see, cop pulls you over, your not dirty so you agree to let him search your car...and BAMMM! "What do we have here?" says the police officer. "I don't know, it's not mine" says you. Cop gets your home address off of your license...
...the possibilities are endless at that point. May not be a worrie of yours, but.....I'd be a paranoid mofo at that point.