I posted this on another thread about a shanty being broken into but here is my idea again.
Cut a 4'x4' hole in the floor directly inside your doorway and hinge it to the wall and latch it open that way.
Cut out the ice in this 4x4 spot and completely remove it from the lake each time you leave. Put an el-cheapo lock on the door they are sure to bust.
Only you know to lower the floor when you arrive.
I suspect it would go something like this:
First drunk scumbag breaks lock while his buddy plays lookout on other side of the shanty.
Scumbag one falls in and ends up under the ice. Scumbag number two goes in to look for his buddy and succumbs to the same fate. If any more arrive I suspect at least one from each group may end up in the drink much like a multi catch mouse trap. Thus putting an end to the shanty break ins in your area.
You could even devise a rotating block of ice that flips over when they step on it like a trap door of sorts for even better odds of getting them.
In reality a good lock and Hasp will help keep out the riff raff and keep you from getting in fights or being sued for a booby trapped shanty.
If they still get in you aren't really any worse off and most will probably stay out anyway.
