Gallbladder surgery seems to be a question over here on a few forms. Stones (from the liver) can still cause problems for some people after it's removed so perhaps it has a waiting period....will have to ask the question, under an assumed name lol...
I'm amazed that insurance pays out on anything, some of the guidelines on policies here exclude cover for; being treated for anxiety and/or depression; any doctors visits for back problems so it won't cover you for any damage to the spine. So if you have been to the docs for back/neck ache and you get run over by a bus and break your back, your back may not be covered. So those two conditions alone probably exclude a good percentage of the population being covered.
I'd rather pay more and be covered but with one company even that wasn't an option, just didn't want to know. Being Brit/Aus does cover you for emergency treatment in quite a few countries who have agreements but of course it's always the plane journey that needs covering as that could get expensive.