By rights they should give a depth of ice that would be safe. A D7Cat and 3 heavy sleighs needs 4 ft and even then the ice can be broken and that is never a good thing. Might as well belt yourself in as they will look for the equipment rather than any missing bodies.
Oh yeah..............and not just for the lift. I figure the truck could be a write-off. Then any repairs needed to the hoe. Now the lift. Costly lesson.