Many a person can surly recall a tale of them falling in or someone they know and can state how the life jacket saved them - but I have never known a story of someone on the Broads fall in, hitting themselves on the head as they did and rendering them unconscious as a result.
i know off one person who fell in getting on a boat ,and broke a rib or two, in his case an auto inflating lg would have killed him , he was pulled out from under a dive deck, if he had an auto life jacket on chances are you wouldn,t have been able to get him out as he would be more pinned to the dive deck(reedham)
It,s all chance the same risk every time you get in a car.....people die everyday .....tommorow will it be you?