> We reply to TrueCaller to suggest that:

...

> They send a SMS to any non-user whose number is entered to warn them someone is attempting to enter their number and ask them for consent. This would also be an opportunity to inform them about the unlisting option

For this to be effective in cases like the one in the story, the SMS would have to be sent almost as soon as the attempt is made to add the number.

In many cases, that would allow the person whose number is being added to infer who tried to add it. If the caller is involved in some criminal activity, that could be dangerous for the person who tried to tag them in some parts of the world.