Guide dog owners are extremely responsible, and their dogs highly trained and disciplined. Having dispatched a flight on Monday with a blind PAP and his dog, I saw this in evidence. The passenger requested beforehand that he be able to take his dog outside to allow it to relieve itself prior to boarding the a/c, and having facilitated this, the dog duly obliged without delay. No risk of the dog having any accident on board.
If only parents were able to train their children to the same standard, or act as responsibly.