Character mistake: When Randy is introduced for his semi-final match, he comes out to "Rock of Ages" by Def Leppard. The announcer says the song is by the "supergroup" Def Leppard. A supergroup is comprised of band members who were previously successful solo artists or band members prior to joining this band. Def Leppard is an original band. None of the band members were famous or successful prior to this band. (00:03:00)
Suggested correction: At best, this is trivia. Perhaps if the announcer was in the music business and knew the music jargon, it could be seen as a character mistake. I myself never knew "supergroup" had a specific meaning until you mentioned it. To me, it sounded like he just thought Def Leppard was super. Like calling them a totally radical group, despite no members being radicals - someone who wants complete political or social reform.