[lapcat]

Why do you assume LinkedIn is correct? I've seen multiple social networks pull the scam where they claim you've violated their ToS only to demand your phone number and other personal information for "verification", and then after they've slurped your data, they don't seem to care about the so-called "violations" anymore.

[marssaxman]

Twitter pulled that stunt on me: within minutes after creating an account, having done precisely nothing with it yet, they locked me out with some vague complaint about security and suspicious behavior, demanding a phone number. I refused to comply, and several weeks of daily complaints to customer support eventually got the account unlocked, with no explanation; they are clearly just harvesting numbers for the sake of it.