Based on my experience, they do call the police, at least sometimes. About four years ago, I was at Rapid Fire Bunker waiting for my CBI check, and two Littleton officers came in, walked right up to some guy like they knew him, and told him they need to speak with him outside. As I was leaving the store about fifteen minutes later, I saw that the guy was handcuffed.
I'm sure it wasn't about parking tickets, as I had a few unpaid ones myself, and I was approved to proceed with the transfer.