The following is my longstanding firm policy in the event someone asks me for any kind of contact information about another. I’ve written it as instructions to make it easily reusable:
1. Tell the requester that you don’t give out others’ personal information without permission, including the requester’s own personal information.
2. Tell the requester you are willing to attempt to tell the person that the requester wishes to reach them and to give them the requester’s contact information. Be clear that you are not delivering any specific message beyond the requester’s desire to reach the person and perhaps, at your discretion, the general reason for the desired contact.
3. If the requester wants to do this, then
a. Get the requester’s contact info.
b. Inform the requester that you will not provide him a confirmation that you successfully delivered the message and that you will not be providing a return message. This is a one-way, blind street with zero feedback always. You are not a two-way messenger but are in fact just doing the requester — and possibly the other person — a favor.
4. When delivering the requester’s contact information, be clear that you’re not interested in whether the person is going to contact the requester. That is most assuredly not your business.