Review on C.T.Johnson TCL1-YL Deadbolt Blockhead Trailer Coupler Lock - Secure Your Trailer with Ease by Greg Bloom

Each trailer guard can be bypassed. It's all about adding layers of security to make it harder for scammers to steal your stuff. I would give it 5 stars but it is aluminum not steel. Very easy to "bend". Take something like that for the trailer hitch I think and get a toggle hitch and a wheel lock and run a heavy chain, albeit around the axis, take some cameras and put a hidden GPS somewhere in the trailer so you can track your Items can be returned if they are stolen.