He didn't (and couldn't) know that.
All he knew before he turned into the parking lot was that HE was going to give the cop a hard time if confronted. He hit the jackpot when the cop took the bait.
If the cop would have kept his cool, there's always the delete key.
Since he’s registered, don’t you think you ought to follow protocol, and include him in your replies if you’re going to make accusations about him?