Enid first mentions them in "Do You Have Any More in the Back?" when she laments that she will miss every one of their concerts if she is forever trapped in the stockrooms.
Enid and Rad secretly practiced a dance routine to one of the Shade'O Boyz's songs together in "KO's Video Channel", which K.O. posted online. It is likely that K.O. is also a fan of them, as he used another song of theirs for an AMV in the same episode.