Nebraska I see the application for it there. My thinking is that
first, airboats are tippy, its not unusual to lose your balannce on board when not seated and grab for something to stabilize yourself. Bad thing to have there for an erant emergency hand to hit or grab.
Second , its not unusual for folks to get tipped out of a boat even from the seat. Either in rapid deceleration or collision, here again you don't want a boat taking off at throttle with no operator. Thats the reason we put those little trim tabs on the rudder so if ya do get dumped the boat will just idle around in a circle and come back to you. Rigged correctly a man overboard doesnt need to be an emergency, just wait it out a few seconds and climb back in.
I'm not joking about those little trim tabs, they are NOT to trim it to run strait, they are to make it run a little circle at idle.
EDIT: Wording change: The trim tabs are to relieve the perceived stick pressure when operating the boat. Adjusted correctly you will not have a heavy stick and the boat will still be allowed to turn in a circle on its own at idle. You never want to adjust them so the boat runs strait ahead hands off,
ever. ( This is a CYA wording change for the pilots in the crowd LOL
Again I'm thinking Florida, and slack or at least not high current applications.
Scotty