and whats wrong with the owner/pilot standing next to the plane and saying 'yes, it takes avgas'? Are we not to be believed?
If we are so clueless, whats to say we buy the right decal?!
Sounds like a protection against the growing compensation culture to cover the arses and simplify the blame game for the inevitable wrong-fuel scenario.
This happens with shocking regularity with cars so don't see why someone renting a piper for a day should be any different ;-)