I don't know, we've been doing it for years. Maybe it's a regional thing? One account for me and one for my kid. I authorize the use of my games for his account on his machine (I need to login with my account on his machine to authorize his machine, I did it just the other day as the machine authorization only seems to last for a while). Then he can install and play any game of mine I allow (or all) once he logs back in with his account.