I think sometimes we are our own worst enemies in this regard. I have been in the back of many airplanes where the seat belt sign did not come off for the entire flight (some well over 8 hours) even though it was absolutely smooth for 95% of the flight. The U.S. carriers are particularly guilty of this phenomenon. If the seat belt sign never comes off people become a little conditioned to behaving "daringly" to use the restroom. We can't expect people to "hold it" for an international flight.