I've seen ski lockers that were not sealed, and were actually part of the bilge. As long as the boat didn't carry too much water in the bilge, it just drained. They were always pretty far forward, so if you had that much water in the bilge, you've got bigger problems than wet water skis.
If the rest of the cockpit is already not self bailing (as is generally the case in boats like this), then that water would just run over the floor back to the bilge anyway. This really wouldn't be changing that dynamic.