When I flew for JAL, the flight attendants were seated any time the fasten seat belt sign was on.
Now that I am back in the States, I can't believe some of the stuff I am seeing. Take a look at
www.ntsb.gov and you will see at least one flight attendant or passenger each month receiving a serious injury from turbulence.
On one flight, I was flying non-rev and witnessed two flight attendants serving in moderate turbulence in a thunderstorm, and they thought it was funny. Poor judgment.