Releasing Pin before selling Bold

Trying to sell my Blackberry Bold but I have a few questions. It's currently unlocked (was unlocked about a year ago, Crackberry had a giveaway for unlock codes for the Bold at the time) but I was reading around the forums and apparently I need to "release" the pin or whatnot before I sell it (I however, wiped it clean via options).

That being said, I called AT&T (although I'm currently using a Razr as I don't have the money to pay for internet so I can't be using the Bold now) and since the Bold isn't connected to the wireless account (since my SIM is in my Razr) I am unable to get customer service to help me. They claimed that if anyone from another service provider used my phone (T-Mobile or whatnot) the phone can stop working altogether and they might also get my e-mails. Is he spouting BS and am I screwed as I can't release the pin? Thanks in advance.

Call CS again, until you get a rep that knows what they are talking about. They release the PIN so that the next person won't get your emails on the BB when they register it to BIS.

I gave him my IMEI number and he said it won't allow for that, is it safe to assume he's BSing? Since the phone isn't on my account anymore... never had any good experiences with AT&T CS