Re: Clearly bollocks.
>That's easy. I don't have friends who use that :)
The only way you could be sure is to know that no one regards you as their 'friend', enemy, contact, etc., sufficiently to put details in their Contacts list. How would you know that? How would you be aware of people who /do/ know you and store information about you without realising to whom it's sent to or thinking it worth mentioning?
>Them having my publicly available phone # and email addresses aren't exactly a matter of concern.
... web history... dating apps... financial history... tagged images...etc... etc?
Such information is accumulated, indexed and sold on. Companies and their data assets are bought and amalgamated. The pieces that hang from an IP address, a MAC address, a Wi-fi access point are amalgamated. Somewhere, some day, someone adds a piece of information that humans recognise and you are no longer a number, or a free man.
Good on you for trying, but the Zuckerborg, Googleplex, etc. are enormously more powerful.