Once your ID is tied to a account it still counts even if you don't have to use a ID for the trade. For instance if you have two separate accounts and both of them have had a trade in with your ID. Your ID will be locked to both accounts so if you hit a ban on one account it will effect the others that are linked to your ID.
But if I’m using a friend’s account, how would they know? I suppose they could ask randomly, but they’ve only asked me once or twice on the first day of having the account and I think it was because my ID hadn’t been associated with my account yet. Haven’t been asked for ID since.