Aye, and shit happens with a splash.
Also bear in mind that most people have 20/20 vision when it comes to hindsight.
When we were in the area we went blackwater tubing, which involves sitting in a modified inner tube and going down rapids. They didn't warn us to lift your arse out the tube a bit when you go down rapids, but you learn that quickly. At the finishing point there was a plaque remembering the 7 or so people who drowned in the river the year before when it came down in flash flood. They didn't tell us about that either. Not that it would have made a lot of difference.