If the seat belt sign has been on, and the air has been smooth, *AND* I really have to hit the head - I'm not going to honor it unless the Captain has been very firm in telling the passengers to remain seated for anticipated turbulence. And, in 20 years of flying with that personal rule not one F/A has ever sent me back to my seat.

Obviously, they can't expect everyone to stay in their seats for 8 hours. Did anyone else get up to use the lav?