Im with Scott on this one.
Mine have only ever been finger tight. They should easily spin off just by hand. And as previously mentioned, sump plug/crush washer is easy as to get to as well. 15 mins work. (Mind you - I only use 4 bolts on the undertray.
One on each front corner, and the 2 rears that are in the holes about 2-3 inches apart).
Brent.