It is to do with safety, rather than in the rules, but I think a minimum weight limit should be confirmed. I was thinking about building a tiny little heavyweight, light but small, make it harder to get hold of, and maybe make it interchangable between middle and heavyweight. Id also love to see robots like Maxus put 5kg more armour on and compete as a heavy. However, Im not gunna build one like that if I wont ever be allowed to fight it with all the flippers around. Id make it heavier and change my design completely.