https://securityboulevard.com/2019/0...acy-violation/
"Users are complaining that the phone number Facebook hassled them to use to secure their account … has also been associated with their user profile — which anyone can use to “look up” their profile. [It] allows everyone — with or without an account — to look up a user profile based off the same phone number.
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Worse, Facebook doesn’t give you an option to opt-out. … Although users can hide their phone number on their profile so nobody can see it, it’s still possible to “look up” user profiles. … There’s no way to hide it.
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Facebook spokesperson Jay Nancarrow told [me] the settings “are not new.” … If a user doesn’t like it, they can set up two-factor without using a phone number."