FYI, T-mobile has a list of all IMEI matched up to its respective device. It's up to T-mobile whether or not it's black-listed. That's why sometimes when calling CSR, they will be able to call you that you have an iPhone despite T-mobile not carrying the iPhone. You may argue, "nexus14, when I log into mytmobile.com, my phone shows up as a blank image! therefore, T-mobile must not know what phone I'm carrying."
Wrong. T-mobile knows -- it's either T-mobile doesn't have a stock image of your device or it hasn't been programed into their website yet. Regardless, there exist some sort of master IMEI list that links up to each respective device.