motorcycle or helicopter?
I'm a bit surprised that a lot of people consider the risks of motorcycle riding/skiing the same as the ones involved in helicopter flying (not to talk about the guy mentioning ejecting off a fast jet).
Should you crash your helicopter, your head/helmet isn't really gonna be sliding long distance over the pavement or other surfaces getting caught in obstacles and what not (if it is then I believe it was the end of the line anyway). The idea is that your seatbelt keeps you inside the cockpit, isn't it?
And if a "90º force pushes your camera through the helmet" (without it breaking off first), I would also think you were not meant to make it.
I guess the only difference would really be the weight and the angular momentum created by the camera, which most likely would ruin your neck.
Regarding stickers, 3M double tape, and yadiyadiyadas: maybe it does affect the "structural integrity" of your helmet but having had to use my (sticker decorated) motorcycle helmet I can tell you the effects are negligible probably inexistent. If your helmet breaks apart from the forces involved, I would think it's likely your neck (or other body parts) won't handle the trauma.