Don't you guys have chains?!? Never lost a trailer, but we use crossover chains between the trailer and the hitch. If the ball pops off, or something comes undone, the idea is that the chains make a cradle for the tongue to sit it.
No, never heard of, never seen. And pretty sure, it would be forbidden. We have very strickt laws. Every "modification" on a vehicle needs to be approved by officials. But it sounds interesting. Got pics?