[FabHK]

> I suspect any careless flight attendant involved in a turbulence-related accident would learn their lesson after the first time, and take better safety precautions.

They are briefed, no need to learn their lessons after the first time. However, it's part of their job to walk around the plane (eg to serve food), and so they're less likely to be seated than pax. That is the (rather obvious) explanation for the fact that they constitute a very high proportion of victims, not "careless"ness.