I work in the Offshore Oil industry, and every time I go on a helicopter in the UK I have to wear a Bright Yellow Survival (dry) suit, winter or summer. Yes, it can get pretty warm in one during the summer, but with UK water temperatures its not a big deal when considering it might end up saving my life. Offshore workers also have to do a survival course every 3 years too, which amongst other things includes practicing to escape from a simulated sinking & upsidedown helicopter, they call it the heli-dunker for obvious reasons!! RGIT in Aberdeen was the last place I did my refresher training. Anyone can do one of these courses, but I seem to remember an artical in Pilot Mag last year about a course run by the RAF up in Kinloss specifically aimed at private pilots, it cost about £150 as I recall.