in most speed falls there's enough force to 'unclip' you - you're only held in by springs after all it's low speed wobbles and stops that get you so learning to use them is perilous. both times i've come a cropper it's been down to loss of concentration at low speeds - either talking or trying to do too many unfamiliar things at once, was realy paranoid about unclipping this morning though so no accidents today.