t-mobile provides you with the ability to manage your account online - great! If you ever lose your password, just go to www.tmobile.com and the system will automatically SMS the password to your phone. Sounds smart at first.
What happens if you lose your cell phone? Now anyone who finds your phone can go to t-mobile.com and have full access to your account, including payment information.
One would think that t-mobile would have been more conscientious about texting a password that gives the user of the phone full access to the online account. But no, t-mobile wants to save on support calls and chose instead to compromise system security.