Definitely one hell of a lot better than nothing. :)

A u shaped bicycle lock requires different approach to be defeated than a chain. I would suggest a chain on one side, bike lock on the other. I like the boot pictured above too.

Here's mine. Just take the coupler off the trailer.
BTW, the large wasp nest inside also keeps people honest.

http://forums.pelicanparts.com/uploa...1467679900.jpg

Paul would it be stronger if the removable piece was sleeved in or over the trailer frame for more contact and less weight or stress on the two bolts?

We are using this hitch lock.
https://www.amazon.com/AMPLOCK-U-BRP2516-trailer-coupler-inches/dp/B00NUNFKS6

^ That doesn't look like a heavy enough trailer to worry about tongue weight.

As I mentioned, I take the hitch off also, and all of the wheels. Why leave one for them? I just use the cordless impact driver and zip the lug nuts off and take those too.

You could also use a welded on pintile hitch. Fewer people use those, and the thief would need a pintile to steal it. You could also use transport chain to lock the trailer. It's a very tough steel that will not shatter. I use the biggest chain that I can buy, and the biggest lock that I can buy. I have probably a dozen of them.