I have lost the same GoPro twice from the adhesive mounts falling off while skiing with the camera. One time was not even in a crash. Now I use the headstrap over my helmet, and hook a little carabiner from the helmet strap to my helmet chip strap so I can't lose my camera. Its nice to be able to not have on most of time so your helmet doesn't always have a sticky mount. Never had issues with it being shaky or unsteady or moving, but if you dropped something big and head banged a lot I could see it maybe moving.
Im sure if you try it it will all make sense once ur in the air - Blow.Jib