Over the years we've read about quite a few boats stolen from people here on the boards and a whole lot more we don't hear about. I'm sure a lot of us use the typical tongue locks but I'm guessing very few use a wheel lock of sorts. Along with the tongue lock, I used to chain my boat to my garage door years ago. I just put an eye bolt on the door through one of the 2x4 supports....pretty easy. I've also set u-bolts in concrete for a couple of people so they could also chain the trailer up.
There's some pretty simple solutions that can help deter someone from ripping off your boat and trailer. If it's a tandem axle, chaining the wheels together is one way or just sticking a piece of rebar through the wheels from one side to the other would work. With those options, there has to be slots or holes in the wheels.
When I bought the new house I would have had one of those cement blocks put in the floor but did not think about it plus it was too late. I have thought about getting it done but don't want to tear up the nice poly floor