I have never seen any clause or exclusion in any insurance policy saying this would be the case. Surely it has to be in the contract and can't be just added willy nilly. I wonder if it is just an internet rumour that has gone viral.
If they wouldn't pay up, I would say show me where it states that.
Edit: just seen the post above so social media strikes again amongst the 17 year olds that can't live without it.
The internet is full of information, and sh1t, in equal measures.
Also did you know that should you go out when it's snowy and cold, and the Utility companies find out, they can switch off your gas supply as you have proven you don't need to be warm. Just saying..