Great list.
If I had three operators though, I'd be almost tempted to say "I'm the only one to add fuel to the tractor". IF you have any gasoline cans around (and who doesn't), that is the one easy goof that only takes once and can cause damage. If someone misses a grease zerk or skips checking the oil, it's probably not critical.
Add gasoline one time and you're in for trouble.
I have the yellow 5 gallon cans, but up front, I said "DAD is the only one to refuel the tractor". Real simple/ real safe.
Just my 2 cents.
Ron