To me it simply seems to destroy half the value of having a phone number.

My Bank's fraud prevention team try to call me about an unauthorised transaction? Nope.

My doctor calls me on an unlisted line? No.

My daughter's phone runs out of battery and she calls from a friend's phone to say she is going to be late?

I ask a friend to get a friend of theirs to call me about something? No.

Hopeless.