It appears that AT & T's last encounter with consumer unfriendly didn't teach them much about how not to do things. I just received an update to my cellular TOS that included the following clause:
... may be used to purchase goods ... using your [phone] or online. ... Subject to our policy for lost or stolen Equipment, you are responsible for all Purchases made using your Equipment.
The lost or stolen policy is as follows:
If your wireless phone or other device ("Equipment") is lost or stolen, you must contact us immediately to report the Equipment lost or stolen. You may be responsible for all charges incurred on your phone number until you report the theft or loss.
With SIM card technology they use, if done properly (or more exactly underhandedly), you may not realize your phone is compromised until you get the bill a month later. I understand that if you give your phone to your kids, AT & T needs to hold you responsible for the actions they do, but this goes too far. Credit card companies and the like have ways to challenge charges, so should this.
The full TOS can be viewed here