The Proven industries is the best I have seen, but to tow a trailer all one has to do is connect the chains to the tow vehicle and drive off. Yes, the trailer will bob and buck and bounce, but it will tow just the same, far enough to get to a private place to cut/grind/chop the security locks off. Heck, a thief can just chop the entire tongue off and weld a new one on for that matter (after they steal it).
If you need to be serious then look into those wheel locks like the cities use for parking violations. A braided cable can be cut easily by any ghetto bike thief, so you need heavy treated steel that requires serious grinding to chop off if you want real protection.
If I was a thief and you had a wheel locked, I would just remove that wheel if on a tandem axle and drive away, or maybe just drive away with that one wheel dragging, why would I care, something will eventually break, but I still have most of the trailer...
Think like a thief to catch one.