Holy Crap is right... that's why congregating by the lavs is a big issue.

As to manipulating the seatbelt light, or neglecting to turn it off, I had a flight two weeks ago from CDG-DTW on NW where the light was on almost the entire flight, there was no turbulance at all. At one point after leaving the WC I stopped by the galley to refil my water bottle and the FA (who probably didn't want me hanging out while she sat and read her book) told me to sit down because the seat belt sign was on. I smiled and said I would, then poured the water from the big bottle into my bottle the way I always do- by holding the big bottle an inch above mine, so the mouths of the bottles don't touch, (like safe sex) and, of course, since there was no turbulance, I didn't spill a drop.