There's a growing tendency for the skipper to play safe and leave the seat belts on for hours at a time - once recently after a prolonged announcement about staying put in one's seat. This is fine, for freight, but hundreds of people can't do without the loos. They've become miniaturized and down in number anyway, saying you can't get to them is just another last straw. (about the 10th last straw on one flight, last time.)
I was one of the first people I know of that asked my passengers to 'Keep your seat-belts lightly fastened whenever possible when the lights are not on.' People knew what I meant, and when I put the SB lights on, it meant I needed people to get strapped in.
Last 10 SLF I did, the lights were on so much that they were meaningless. There was some occasional light chop, and of course, I wasn't privy to met reports, but there was nothing but blue sky. People just gave up waiting for permission to go to the loo. CC made no comment during the whole 10 hours.