I set myself as an authorized user on the ATT website, but have a few questions. We are current ATT customers, do they need to do a credit check? The account holder (my brother) wont be in the country at the time. Also, when we set the family plan up, we got 3 phones, and even though my brother is the account holder I took the primary sim, meaning my number is the primary line on the account and shows up as such on the bill. Will this cause a problem?