Except that verification for BP purposes is very different than calling purposes. To fly on a BP, you have to show ID to the airline contractors before you're allowed through security, so they know you're the person with status.

When you call, they ask you for your PIN (not just your FF#) because they wnt to verify it's actually you and not somebody who happened to find a BP in the trash bin by the baggage claim that said "elite" on it.