[EricH]

It's only a stupid risk if you don't adequately prepare: helmet, life vest, make sure the boat doesn't have any holes, extra paddles, float plan, all that good stuff. In a car, wear your seat belt and drive defensively. These things mitigate the risk to manageable (i.e., if something does go wrong, it is not necessarily your fault).

Mitigating factors were not present in the photo--even a set of bolt-on handles would help, as they'd provide a more secure (and safe, most likely) grasping area, or a helmet for the case of a sudden stop without preparation.

When the Mythbusters do something with the "do NOT repeat NOT try this at home" message, you'll notice that they're always a) wearing protective gear or b) hunkering in a bunker or c) very, very far away or d) not being in the "line of fire" themselves or e) some combination of the preceding. This does not eliminate the risk that something goes horribly wrong. However, it reduces the damage when and if it does, and ensures that nobody gets hurt.