I wouldn't trust it either. I'd be afraid to start the car everytime I go near it and have slide under and have a look and see if its still closed lol........
I like the idea of it!
It is the messiest part of changing the oil, I use a socket on a long extension to remove it then clean it off after!
This valve wouldn't suit me as I'm a strong beleiver in magnetic sump bungs! I have the Zero Sports one,
Good idea,
Dan