There are things that happen on whitewater that only experience and training, and learning from people with more experience and training than you, can provide.
Saying that people can go do class IV whitewater without any of the above, is, well, lying and also setting you up for a lawsuit from the victims' families.

Rolling with bad technique is a recipe for shoulder dislocation, your paddle float will not prevent that.

The paddle float would have done nothing to prepare the paddler for dealing with this:
https://vimeo.com/22007023

I know I worded this strong, but marketing the paddle float as a substitution for skill is wrong.