Use this as a mantra: "Keep your heels on the floor unless you are braking for landing, or parking!" Period. No discussion OK? Having sat next to someone who twisted themselves in their seat so they could apply lots of rudder in a strong crosswind take-off, and in fact applied lots of asymetric braking instead, and blowing 4 tyres on a 747 after an abandoned take-off, there should be no discussion. At times of high workload, if you lift those feet up, you will press brakes without realising it.