Maybe it would be better if it worked by a system of strikes? Like if one of the accounts that you are sharing cheats, that account gets banned and yours get a strike, this strike means you and the other accounts that use your copy are more closly and harshly monitored but you can still play, if another cheat is detected in that copy then you get a ban.
This would give breath room for parents to explain to their kids that they should not cheat without leaving that much leeway for cheaters themselves.
That would require every single game/anticheat to implement a "closely monitored" feature, and also still effectively halves the price of the game for cheaters.
Additionally, this only benefits people who share their game with cheaters - just don't do that. If you can't trust someone won't cheat with your copy of the game, they probably aren't a close family member.
This would give breath room for parents to explain to their kids that they should not cheat without leaving that much leeway for cheaters themselves.