Written by KD:
How about locking a towing ball in the socket with a padlock and a tire lock on the tires to prevent theft?

How about your own bandsaw used to cut those off??
I don't think it is about having enough safeguards in place, I believe it is about not leaving yourself open to theft by not leaving anything in a place where there is a remote chance of it being stolen. Even working on a job in the nicest neighborhoods the guys you are working alongside all day could come back that night and take your trailer if they know it is there.