The blacklist was created suppose to help cut down the cell phone stolen problem is the US. I do believe in that system and I hope to see the results soon. However, it has some negative impact. Many people purchase used cars or re-owned as what they may called these day. I buy used phone because I don't want to spend money on a full retail price. Many people do that as well. We know how to avoid stolen phones. T-Mobile has provided a web site to check for IMEI and that's very helpful to people like me.
I have learned from other people who buys used phone like myself. The IMEI was clean at the time of purchase. Then, few days or a couple of weeks later, it get blacklist. At this time, it only happen for T-Mobile phones. T-Mobile offer the the payment plan. Many people take advantage of that. There are a few people take advantage of the plan. They sold their phone and stop the payment. T-mobile then blacklist the phone after they can't collect the payment. I think T-Mobile can help stop this scam by adding a feature in their IMEI check site. Beside telling the IMEI is good, it should also provide information if the phone is on payment plan. That will help user phone buyer like myself get rip off.