No ditchings so far, but have had one nasty swim in Spring whitewater after canoe filled up with water without benefit of thermal protection.
It's quite rare that I do find myself dumped in the water, but the wetsuit and or drytop goes on when the water is cold, even though it's no fun at all getting the drytop on.
In waves, you will be surprised how much of the time you will be underwater even wearing a lifejacket
Those who think a lifejacket and/or thermal protection are not needed are encouraged to take a dip in a local pond this time of year -- just make very sure that there's sufficient qualified personnel available to pull you out and dump you into a hot bath in case you get into difficulties
