The force your refering to is just inertia (a body in motion will remain in motion unless acted upon by an outside force). This is a comon mistake that people make mistaking intertia with centrifugal (which does not exist). The ball bearings remain in the shaft until the air inside shaft pushes the balls out and locks the gear.
Even if they did push out the balls would be forced back in by the rotation of the gears and shaft