Starving the engine is not all that hard on it, and surly not compared to running it aground. . .
Numerous fuel shut offs . Remote fuel filter
separator among others which do depend on the engine in question. I could no doubt show you an easy cure if I could look at the engine ... In an Emergency
why do you see a need to shut down versus go for neutral? Some times you might but not all the time. Its not a gas engine so many of those fire problems don't exist.
and the trash bag over the air intake is very do-able as well. It cannot BTW get sucked in unless someone has jury rigged the intake filter and that would be stupid! Yes your basically flooding it out but that's possibly better than what you might have with a runaway.