Virtual Communication with Clients: Progressive or Source of Discipline?

I am a new attorney. I planned to offer legal advice through phone calls and web cam. A local experienced attorney told me that (advice via phone calls particularly) is problematic because you could not verify the identity of the client, and that as your business grows, you will not remember their voice or issues. Thus, as practitioner's we risk divulging protected information to a non-client.

He gave the following example. He had a murder case and his office was contacted via phone by folks representing themselves to be the defendant's family and asking for case updates. He allowed them to question him, and responded that he could not release the particular information. He asked who they were, took down their info, and at the end of the conversation disclosed that he knew that they were the victims family - because all of the defendant's family was deceased. The murder charge was lowered soon after.

From a virtual practice perspective, when a client purchases legal advice via phone or web cam, isn't their registration, acceptance of the limited service agreement and submission of payment a verification of identity? Am I missing something?