That's why the magic words are "Am I being detained or am I free to go?"
Personally I agree with Bats. I've gotten out of more tickets just by being polite, respectful, and joking around with cops then the "I know my rights!!!" whackjobs. However, I have gone that way too when said cop is being a dick a for no reason. And they've never done anything but let me go on my way when they realize they're not going to win. Shit, I spent 3 years in court fighting a ticket because the cop was a dick and I ultimately won.