"Richard Casady" wrote in message
...

You people are all nuts. You label the opening, not the cap. Caps can
migrate. One more thing to go wrong.

Very unlikely to migrate I would say:-.
Would anyone have either the water or the 'waste' caps off while the fuel
cap was off.?
Would anyone have either the fuel or the waste caps off while taking on
water?
Would anyone have any other cap off while the waste connection is in use?