It doesn't take 'relaxing' or not flying the sim like you would a real aeroplane- I think people do handle sims just the same as the real toy. It takes heavy concentration on something else- in this case a take-off, and you don't notice that you're pressing on a brake inadvertently. How many people have to do it before it's believed it is perfectly possible to press the damn thing without being aware? And anyone can do it- long term experienced Captain or junior pilots. Just make sure if you think you are good enough never to do it yourself that better pilots than thee have been on the FM's carpet for doing just that!