Thanks. I should have been clear I was asking what blocked meant not what IMEI meant.
So is a bad IMEI always a blocked IMEI or are there other categories of BAD? I seem to remember reading about cloned phones in the dawn of the cell phone age. Are there cloned IMEIs to allow multiple phones on one plan? I realize something eventually stopped that from working back in day but is there a new round?
And if a blocked IMEI is due to the phone being stolen does that mean whoever has it is guilty of possession of stolen property (knowingly if they know its blocked somewhere)? Is there a database of blocked/stolen IMEIs to let buyers protect themselves?
I'm interested mostly out of curiosity but my wife was originally told she could not get an unlock code from T-Mobile because her Lumia that she bought new from T-Mobile and never used on any other carrier had a blocked IMEI. They finally gave her the unlock code but never explained what "blocked" really meant.