Every time something like this comes up I'm reminded of one time I was stopped by a police officer walking down the street. I felt a tap on my shoulder, turned around and was greeted by an officer in uniform, I wracked my brain trying to remember what I'd read on the internet about talking to the police and was just about to blurt out "Am I under arrest or am I free to go officer?" When he told me: "You dropped your wallet a ways back son, here you go" and handed it to me. "Thank you officer." I said sheepishly, and went on my way.

Not to say that this isn't great advice that people should follow in general.