It’s hard to imagine an “accidental” discharge unless the thru-hull valve was left open “accidentally”, in that “I ‘accidentally’ forgot to close (and tie) it” when we got within 3 n.mi. of shore. I think they want the thing (valve handle) locked closed so if you are about to be boarded you cannot pop below to quickly close AND lock it if open illegally. Putting on a zip tie that’s secure would take a few minutes, etc. That’s assuming the CG really wants to catch you in violation in the first place, which I sometimes doubt.
Has anyone here ever been cited for an open or “unlocked” discharge valve? The last time a coastie was aboard, the valves were closed but not tied. I was advised to zip tie ‘em as they left. Think of it. If you’re at the Island and need to dump, go out 3 n.mi., snip off the zip tie, open the valve, discharge, close the valve, attach new zip tie, and then return. Do that again in two or three days.