IMO Most of the time a Judge can pick up faults when actually being hands on not just by looking at the dog in the ring. It happens a lot at shows eg person at ringside things another better lookin dog should have won but hands on can tell ya much more.
As for a Bad Temprement well its up to the Judge to report personal incidents if any and then dogs are banned from showing at KC level

Just leave out the middle man and pick out the prizes from a bran tub....