"Winter Wheels" sold in Europe

I like that idea. That would even work on utility trailers

Taking the wheel off alone would be a big deterrent.
Once the wheel is off do you really need the plate?

do a web search for boots same thing different design

Looking at that thin metal tab sticking out I could cut that off with my cordless 4" grinder or even a hacksaw in less than 60 seconds..

B.O.

I wonder why a hockey puck lock wasn't used instead. I do agree about how fast that metal tab could meet its fate.

However, it definitely would make a thief work for a trailer. The advantage over boots is that even if the thief breaks the lock off they are still hosed, because there are no wheels present. Either the thief has to find some or bring their own, then spend the time it takes to saw off the plate and put them on. If someone used locking lug nuts from Gorilla with the rotating sleeves, the thief would have to get a grinder to remove them.

Nothing is 100%, but it will definitely stop the guys who will use a smaller ball in the hitch or tow chains to nab someone's rig in a storage lot.