oil shut off switch
 

do the ecotecs have oil shut off switches, a sensor that doesnt allow then engine to start if the oil is too low

no. Deffinitly not. If there were then we would make money of the people that run their engines low on oil..

pretty cool idea though. makes me want to make something that shuts my engine off if the oil pressure drops below a certain amount

its called common sence. know ur engine. Check your oil. I know iv always wanted to have my engine cut out going down the interstate at 90. A defeat switch? Then whats the point of killing the engine? Next to that... One mre thing to keep ur engine from running when it thinks ur low on oil and ur not.

according to my grandpa and uncle they existed at somepoint

being that we think my car has a fualty sensor and its got throw backs in the design like the overhead oil filter they were wondering about it

I believe Volkswagen has that system in the their engines.
Edit: my bad, it actually doesn't shut off the engine, but displays a warning that says "low oil pressure, turn off engine!". That's from my gf's 2010 Passat.