Could you change the brake pads on a car in a racing series where all the cars are supposed to be identically prepared. You probably could as it would be difficult to enforce unless you got completely carried away. Just because a rule can be cheated with little to no chance of being caught does not make it ok to cheat the rule, it just makes you a cheater. The fact that we can't enforce a rule about not changing brake balance is the only reason we don't have it. The spirit of S.N.A.I.L. is to run identical cars on identical tires and let the driver make the difference. It is only through an oversight on the part of PD that the tuning of brake balance is allowed. Don't even start on not all cars have even braking between front and rear. The idea isn't to replicate reality with the settings, it's to put everyone in an equally prepared car and let the driver make the difference. If we were going for realistic setups, then the rear toe of nearly every car in the game would need to be changed (along with many other suspension settings).