The devices I have heard of being shut down by RIM are the pre-release test/dev units, often sold illegally on eBay at ridiculous prices. These units have stickers on them saying stuff like "Property of Research In Motion" and "Not For Sale". Once the model is officially released, developers are supposed to return these units. RIM shuts off the PIN permanently, rendering them paperweights.
The other problem with PIN/IMEI numbers most folks encounter is that a used BlackBerry is sold while still associated with the original user's BIS account. Since the PIN is still linked to the first BIS account the new owner cannot activate it on his account. That's covered in the link JSanders provided.
Last edited by rambo47 : 11-23-2009 at 07:07 AM.