Erm, do you mean "worse" as in more money to repair a dropped camera (new body, realigning lenses, etc), or worse if there were two separate problems? In the second case, I'm guessing the repair technician would say "In addition to being dropped, the image sensor is also burnt", and the camera shop would say "okay, looks like you burnt the sensor with the eclipse, and then most likely dropped the camera on purpose", and would cover nothing.
In general, insurance relies heavily on intent. Intentionally breaking the camera on the ground would not be covered. Gross negligence (like ignoring the warning of the camera shop and proceeding to burn the sensor) is interesting because to the person doing it it feels like an accident, yet to most everyone else it feels like they didn't try hard enough not to.
