Is IMEI # detectable by operator?

[siung777]

I'm about to buy used At&t phone from ebay, but it has no box, manual. I'm worry if this phone has reported lost/ stolen. The seller said it is clean. But I'm still worry.
Anybody knows if the operator (At&t) can detect our phone IMEI #?

[albo6]

Every IMEI can be detected with every operator in hall world, so be careful when you buy phone from net!!!

[elias74]

this is quite a risky business, but even if IMEI is trackeable, its quite impossible that something happens to u. It's a MAJOR ONESTY question. It depends on u. I would like to be SURE about what i'm buying.

[ama95]

Buy the phone if you're 100% SURE what are you buying.

[platijet]

theory of GSM says that in any registration ( mobile to the network ) IMEI (only once,after power on the phone and entering pin ofcourse) and IMSI (always: after PIN,SMS,CALL,DATA etc ) given to the network.
the point is if operator HAVE THE BLACK LIST OPTION ENABLE.
for examble here in greece this option is disabled.only VODAFONE use this option for 1 year old PROTOTYPE phones ( given by vodafone as sample)