If you accept modules in Keep Talking and Nobody Explodes as “minigames” then I could name several hundreds that I enjoyed when I was still active in that game. Many of them are “soloable”, meaning, do not require another player with a manual. Several fans of the game, myself included, would sometimes load up a bomb containing only soloable modules and just play on their own.
I think the course of action is clear. Ban it from tournaments/official events. Since I’m not in the LoL scene I don’t know if that might already be the case. Now, regular players will know that playing with this enhanced hardware will disqualify them from tournament play anyway. So now you simply create two modes of gameplay: tournament-legal, and casual. People who aren’t aspiring to play in a tournament will play the casual game and it’ll be acceptable there to use enhanced hardware. People who wish to play with people using tournament-legal hardware will play in the tournament-legal mode. There is little to no incentive to cheat in the tournament-legal game because you won’t be able to cheat your way into an actual tournament that way.
That is assuming that she’s not sharing the name voluntarily. It’s not a GDPR violation to offer such a service if it’s opt-in.