We were there last year during Grad Nites and it only interfered with our touring one morning. We went to get in line for the MGM bus at ASMo and there were about 100 teenagers already in line. They may not have been part of Grad Nite....who knows. We hopped on the Epcot bus instead and decided to stay there until we were ready to go to MGM, then hopped on the boat. We were told that they are, for the most part, bused in to the MK for that one party and then bused back home.