> It doesn't have to be you: your old friend has both, and shares their data with Facebook, Snapchat, and/or Whatsapp (all are Facebook) so you have no hope of

> It doesn't have to be you: your old friend has both, and shares their data with Facebook, Snapchat, and/or Whatsapp (all are Facebook) so you have no hope of concealing this. Instagram, not Snapchat, but yes. That's the main part of how they build "shadow profiles" of people without accounts, afaik.