I know OP said they would go talk to their neighbor but I just wanted to add an anecdote. I worked at a place that had a bunch of trailers, and it wasn’t uncommon for someone to need a vehicle and just leave the trailer in the parking lot. One time someone didn’t secure it and it started to roll. A new guy who was trying to be the hero went to stop it and got his thumb crushed between the trailer and a steel beam of a pavilion. He ended up loosing his thumb. So yeah, chock your trailers and don’t try to catch a run away one.