Copyright is a civil, not criminal, matter so the police should never be involved unless they are alleging a criminal act (such as trespass).
This is a reply to quite an old post in this thread but I want to point out that in England it is different. Trespass is a civil rather than criminal offence and police cannot remove you from property which you are trespassing on.
"People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.