They are never safe, even in an enclosed trailer. I've seen this happen several times at the Pigeon Forge rod run as well. They just steal the whole damn trailer, sometimes even the truck it's attached to, it's crazy.
That's why after I get the family tucked in at the motel, I go out and sleep in the car, with my side arm at the ready.
Too bad you go out to have a good time at these things and you simply just can't let your guard down.
He's lucky he got the car back unscathed, some of my friends weren't so lucky.