I think our Karl is misinformed about T-Mobile's practice. This really is only for AT&T. T-Mobile does block stolen phones.
I had the misfortune of actually buying a Samsung Galaxy S2 phone off eBay as listed brand new from a reputed dealer. The phone was to be used under a T-Mobile service. All was well until one month later the phone simply didn't register on the T-Mobile network. I called T-Mobile and they actually told me that the phone was flagged as being stolen and the IMEI had been reported. I needed to provide the original receipt from a T-Mobile store showing purchase of the device. Since I didn't have a T-Mobile receipt, it became a mere paperweight.
Fortunately, it wasn't too late and I got in touch with the seller on eBay who was good enough to refund me the cost of the phone after i shipped it back.
Bottom line is T-Mobile does block IMEIs.
I think its wrong to state such a thing that T-Mobile doesn't do so. Its probably only AT&T that allows this practice of not doing anything. -- "Look at me, I'm Dr. Zoidberg, homeowner."
had Cingular not done this at all before merger with at&t/sbc?
at&t in general is very reputable to me, the only beef I have about them is higher prices and more anticonsumer monopolistic behavior. I am glad I was able to get 23% employee discount from a large company and get early their $5 for sms/mms and $25 data plan when they were still offering it. This helped me cut bill while allowed me to stay there and stay within nationwide coverage. T-Mobile has very small coverage and apparently where I work now with a reputable large IT company, T-Mobile does not even have service there.