Many of my family and friends have AT&T/SBC for Internet. Remember that you are an always an ambassador for the company you use. If AT&T believes that you’re embarrassing them, you can be disconnected.
There are 3 reasons you can be disconnected; violate Acceptable Use Policy, break the law, and embarrass AT&T, subsidiaries, or affiliates. Affiliates might cover me since I use NTS, which rents from AT&T.