I'm honest about everything: touching the net, touching a ball that is heading out on my side of the court, double hits, my foot-faults, etc...
I will not call out my serves or deep ground-strokes unless they are blatantly out. It is much easier for the opponent(s) to judge that. If i think it's out i will ask "wasn't that out?"
I don't know if this is good form or not.