I think i miss the most important one..

On stage one should never pee heir pants
Not from abuse of alcoholics
Not from fear for the audience
And not from old age...

Espescially not as a singer..
Maybe the keyboardist sitting in the dark corner with dark pants on can come away with it..

But then the pleasure of peeing your pants quickly turns from a warm feeling into a cold one.. so i dont think peeing your pants on stage is a good idea even for a keyboardist.