According to TMZ, Kanye West totally blindsided Billboard Music Awards producers when he performed the n-word laced version of his hit, "All Day" and forced the censors to stand on the audio dump button. Production sources at the award show tell TMZ Kanye never did a dress rehearsal of the song, so they just expected him to be on his best behavior, and perform a clean version. One source said, "He knew it was national TV." His closing act is the one everyone's talking about -- even though they couldn't hear or see most of it. The production source told TMZ, "He's Kanye. What are we supposed to do?" Kanye not doing a dress rehearsal isn't THAT odd. Mariah Carey also skipped hers and several sources told TMZ that's just what happens for top of the A-list acts.