Vicrider ... enjoyed your story, as the old saying goes, "you never know". Managed to tip my canoe over this last season, hadn't done that in a long time. Fortunately for me I didn't have all the fanfare you had, it was a local pond (all alone) and in the warm time of the year, and like you I side stroked the overturned boat to shore, a very short distance of maybe 20 feet. What I had done was to try and look back from where I had been to sort of get my visual markings right to make sure I was going to pass a favorite spot just right. When I looked back over my left shoulder I attempted to place my left hand on the gunnel just behind me so I could sort of support my turning rear glance - what happened is that either my hand slipped off the gunnel or I missed it entirely. Anyway, I simply rolled down into the water taking the canoe over with me. Lost some gear, like my canvas creel, sun glasses, best fishing pliers I've ever owned and a bunch flies. Had a full bottle of water in the creel that made it go down like a submarine, but you'll be proud to know that I never ONCE let go of my fly rod! As I pushed/swam the overturned boat ashore I placed the fly rod on top of it, with still a grip on it however.
Now, I've managed to turn canoes over in years past but with all my experience I begin to think I was just about invincible with my canoe skills. Surprise - surprise - surprise
By the way, I never stand in the canoe, do all my fly casting sitting down. Think I learned another lesson somewhere back about that standing in a canoe and trying to fly cast.