Can the police contact you and run your name even if you aren't committing a crime?

Law Enforcement officers are allowed to investigate anyone they feel is suspicious. And yes, they can "run" you. It would be foolish of them not to. Lets say some guy is hanging out at a bus stop. He's been there for 45 minutes. He doesn't appear to be doing anything, just waiting for a bus. Next to the bus stop is a playground. There are a few kids playing, nothing amusing. The police officer hasn't seen him around there before, so he decides to stop to check the guy out. They "run" him and find out he's on probation and a registered offender. One of the conditions of his probation are that he not go within 1000 feet of anywhere where children congregate - such as a playground. Now they can arrest him, and they might have saved a child's life. That is why cops stop and talk to (and run) people who look suspicious, even if they aren't in the act of committing any crimes.