I had insurance for my underwater gear once--back when I used to dive (I still plan to get back into it!).
That said, I flooded my camera in Micronesia. No problems getting the insurance coverage once I got back. Didn't replace my camera on the trip, though.
I don't know what they thought when two people named "Carey" (me and my brother) both put in claims the same week. We both did the same stupid mistake, which was my fault.