Like Les, I have camera cover on an NFU home contents policy; they coughed up without any problem when we had a bit of an incident in GB Cave.
I was trying to take a picture of somebody climbing the waterfall when a rock, estimated to be roughly the size and shape of a rugby ball, somehow 'got dislodged' and came whizzing down towards the photographer (me) and his assistant (my daughter) and a couple of lookers-on. The rock hit a ledge and shattered into fragments, which shot at us like shrapnel. In the ensuing chaos Charlotte stumbled and fell, and the flashgun she was holding (a fairly expensive Mecablitz) got smashed to bits.
The NFU were quite happy to pay out, notwithstanding that the incident happened underground.
Off-topic ? but one interesting aspect of this incident was that all four of us at the bottom of the waterfall felt that it happened in slow motion, while the 'poseur' and top assistant with flashgun at the top of the waterfall saw us all standing still, and were willing us to move to get out of the way; odd?