During a reject after a sudden cut at/close to V1 with a big boot of rudder to keep straight, I would find it very hard to slide my feet up the pedals to apply maximum braking. I would venture to suggest that it is almost impossible to "slide one's feet up" the pedals whilst applying any reasonable steering force; I would have to virtually pull my feet completely off the pedals first. Obviously, rather undesirable on a balanced-field reject. As far as I am concerned, wherever your feet are at the failure is where they are going to stay for the reject.
On all takeoffs my feet are right up ready. These incidents do however reinforce the need to keep one's toes off the brakes, wherever you have your feet.