For years I've been passing on the message that, even if you are 100% innocent of wrongdoing, the only things you say to a cop (outside of a purely social interaction, of course, or when filing a complaint yourself), are "Am I free to go?" and "I want a lawyer." In this great video, Professor James Duane explains why Fifth Amendment protections are so vital and why you should not talk to the police, even when you've done absolutely nothing wrong.
Did you know that nothing you say to a cop can be used as evidence in your favor in court -- that's considered hearsay -- but everything you say can used against you? Did you know how even things that seem completely innocuous or exculpatory can be used against you in court? Watch the video. It's 27 minutes and 25 seconds that could keep you out of big trouble. (It's also worth watching the next part of this presentation, with Officer George Bruch from the Virginia Beach police department talking about criminal interrogation strategies.)