Downscaling the myriad of signals from your brain to 64 electrodes controlling four spacial dimensions seems tricky. I can see that making a fist may turn left,

Downscaling the myriad of signals from your brain to 64 electrodes controlling four spacial dimensions seems tricky. I can see that making a fist may turn left, but what prevents any other random thought of being interpreted in the same way? I.e. how safe is a bike that turns left upon twisting the handlebars left, you may end up turning right with odds of 1:1000?