Ewwwwwwwwww. Normally I think everyone should do what they want to their trucks and I know personal taste differs greatly, but that's just plain silly.
I'd go test the wires for the sending unit and inspect them as well. If it checks out, you probably have a bad sender. It very much sounds like you don't have an oil pressure problem.
The gauge isn't the problem if you're getting the low oil pressure warning. You either have a oil pressure problem a sending unit problem or a wiring problem.
All you need to do is interrupt the power to the ecm and you'd have cut the fuel. However for a true fail safe, cutting the air supply is the safest option.