Comment by Intermernet

I recently flew ANA and they advise all passengers to keep their seatbelts on at all times when seated. It seems like simple advice. I do the same thing when I'm driving. I don't find it uncomfortable in the slightest, even sleeping. Maybe others have a different experience, but turbulence isn't that rare. I've had serious turbulence on many flights. Probably the worst was final approach / landing in Frankfurt with perfectly blue skies. The atmosphere does weird things.