I think signalling is a great idea, although I have never used it. A friend taught her two Bichons to do it with a bell at the door. My dogs always let me know when they needed out. We had a regular routine, but if a potty break was needed at some other time, restless pacing and trotting toward the door was a pretty clear picture. Never a problem.
Worst thing is the sound of a dog beginning to retch and jumping off the bed at 4 a.m. Seldom managed to get outside quick enough!