The best part about a bang stick is you can employ it while still under water, drop it, and swim away without anyone ever seeing you!I can't begin to count the number of times I have yelled at idiots in boats for driving right up to a dive flag and start messing with it. When I have had my flag messed with I wish I could come up with a 12Ga bangstick to their engine compartment.
I have stopped using flags most of time because it creates more of a hazard than to not have one.
Engine blew up? Man those dolphins are getting rowdy these days!