my friend is moving across country and picked up a small u-haul trailer. it does not have a coupler lock and he is worried about theft of the trailer while he is sleeping in a motel. we looked at the safety chains and came up with a way to paddle lock them but they are no match for cheap bolt cutters. the only other thing i could come up with was a battery powered motion detector that sounds a 120db alarm if the trailer is moved. the problem with that, as i see it, is that if he hears the alarm, and goes out to find three hulks who challenge him. he's the type of guy who would not back down from a challenge...ever. he thinks he'll just beat'em up enough that they'll think it's not worth it to continue. he refuses to take any means of protection with him. i have offered him my OC w/ CS military gas but he won't take it. i don't know why he won't at least pack OC(pepper spray). although the CS gas brings added responsibility for proper and necessary use, it also brings a quicker end to the threat. not only am i worried about his trailer, i'm worried about what might happen during an attempted thievery. any thoughts on how secure a trailer without a coupler lock?