Let’s face it; using public toilets is never a pleasant experience. Putting aside all the legendary messes you have encountered, even if the restroom is immaculate you still have to worry about yourself. As stealthily ninja-like you try to be on the can it is virtually impossible to do it without making any embarrassing sounds.
This is especially true of the fairer sex who often do a courtesy flush but in these ecologically sensitive times it’s hardly a sensible use of a gallon of water.