The reason they ban the driver too is that if he got a ride in another car for a couple of races and got points then won at the end of the season or finished highly, he would have "BAR" on his overalls and they would get the credit for his win i guess, either that or its just a case of "everyone ascociated is banned and if he doesnt want to get banned again then he should join a team that dont cheat"

Its irrelevant anyway probably as no other decent team would lend him a car for a couple of races.