IMO the cheater is kinda a peripheral part of the story anyway, it doesn't really matter and probably won't have any real impact on the story, like the chess guy beating the math teacher, sort of just part of the lore and background of BaDIK
But if it ends being important like the cheater gets caught again and ends up kicked of B&R in a dramatic way, well, Lily is kinda a good character for it, we already know it's not a main Li, can't be Josy (Taylor), Maya (Bailey), Sage, Jill, Bella (lol), soo... what's left anyway, are other characters, and Lily is not that peripheral to the story, she's part of it, contrary to those really side characters like Tara Tiffany, Beth and co.