Does your org have a benificial suggestion process? Make a suggestion that when they solicit contact info for their records, they ask for BlackBerry PIN. I know PIN's change, but so do other contact details. When an individuals contact info changes, it's their responsibility to notify their contacts. If you ask for PIN, it would inform them that their PIN is part of their contact information for your org. At least you will get PIN's for those who use blackberry.