> Try register on Twitter. They'll let you register but then randomly suspend your account for alleged ToS violations (even if the account was outright inactive) but will give you the option of instantly unbanning yourself following phone number verification. Microsoft will randomly lock out MS accounts without a phone number attached and will require a phone number for "security" upon the next login (the security angle being very dubious considering they don't have a number on file to compare to, so even an attacker can pass this challenge just fine). Etc.
I have accounts with both of these orgs, not equipped with 2FA and none of what you describe has ever occurred.