Let me tell you something from my first hand knowledge.... I owned a chain of indirects... and delt with this exact issue.

I had some guys that tried to sell me some bran new treos out of a trunk. When I called in to check IMEI's they told me they were all clear.... but when you get them at 50% activation price somethings gotta give.

All you can do is call in and ask.... I will tell you that the only carriers that you can get a definate answer is from CDMA carriers becuase they can black list the phone from use.

However a GSM carrier....it really seems that they don't give a crap. I bought quite a few phones from these guys until I was contacted by law enforcement..... they asked where I bought them (becuase I was selling them on ...
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IF its a GSM phone you don't have to worry. It will work (unless someone set a security pass code. When buying used phones make sure the phone is completely reset so you can set your own codes.

Flexibility and freedom has it's price as well. IF your phone gets stolen anyone can use it. I thought ATT had IMEI numbers. They do but apparently will not render a phone useless. I think that's a good thing. Just hang on to your phones and be wary where you buy them. I buy used phones and never had an issue with them not being factory reset.

this doesnt mean it was stolen if you purchased the phone from an agent, it could have been bought directly from the manufacturer and at&t doesnt have it in their system.

i saw this problem when a customer came in my store with a hot pink razr which as we know is designed for tmobile, well the customer had a receipt showing the imei was purchased from an at&t authorized dealer and the phone had at&t software and branding.

if its a warrantee issue, enough bitching should get you through with that department thats all i had to do i even offered to fax over a copy of the original receipt ... and if all else fails go directly through the manufacture...