If everyone is doing that does it really mean anything as far as competitive advantage? Does 10 lbs really make a difference compared to if you trained for maximum strength or endurance while your competitors were playing games with the scales?
Everyone does it.. so it evens out. But if you don't you are the odd one out. It is like trying to win a big cycling race without juicing. Sometimes you have to do stuff you shouldn't just to have a fair chance.