Heels should be on the floor for take off and on landing until initiating manual braking
I completely agree.
If (and it’s a really big if!) that means you go off the side of the runway on a low speed abort at 30 or 40 knots, that’s totally survivable. On the other hand, inadvertent (differential?) braking at higher speed is a very different scenario. Where do the greater adverse consequences lie?
Does any manufacturer recommend ‘feet up’ for take off? I’ve flown five different jet liners from three major manufacturers and I can’t recall it? Or is this just a ‘bright idea’?