What happens when you add someone as a contact on the BBM (Blackberry Messenger) iPhone app?

One of the people I'm following on Twitter put a post on his page saying to add him on BBM, and then put his pin/username. But it was back in January when he wrote that, so if I go onto my BBM iPhone app and type in his pin/username, will it add him straight away, or will it take me to his profile so that I can check it's the right person before I add him (similar to Facebook)?

I'm worried that he might have cancelled his BBM account since then, and the username/pin would have been given someone else. I don't want to add a complete stranger to my contacts.

This will be the first time I've used this app, so I'm not sure how it works.

What it does is sends them an invitation to add you as one of their BBM contacts.

BBM numbers are not like phone numbers, they are device specific. So if this person had a Blackberry phone it would only be to that phone that invitation went to. If he had a BBM app on an Android or Apple device, that BBM pin number gets generated when the person creates an account, so even of his pin was re-issued (unlikely since they are totally random), The NEW person with the PIN would not even know about any invitation that was sent BEFORE he got his BBM PIN.