This reminds me of a news story about a flight between somewhere in CA and Hawaii maybe ten years ago. The turbulence caused flight attendants and some passengers to hit their heads on the ceiling of the plane causing serious neck/head/other injuries.
I fly a decent amount, and ever since that story I really pay attention to buckling up even more than before.
about seat belts....the other thing I do is I never use the airplane br...I'm always buckled up....of course I watch what I drink so I don't have to go to the br....