I've been to several open shows recently and have stayed to watch the final judging for 3.  Now tell me if this is co-incidence or what, but the BIS judge gave the BIS to the dog he had judged in either his breed class or the variety class he had judged - ie put this dog through to the final. 
As I understand it, the BIS judge is offered other classes to judge in the show, but surely he must be biased to the dogs he has picked out.   Surely it would be fairer if he didn't judge any other dogs in the show?

Can't speak for others but it would make no difference to me, in fact seen dogs may be at a slight disadvantage because they are not fresh in your mind unless they made a big impression.