[mimimi31]

Also mass locking Microsoft accounts that were created without providing a phone number[1].

For some reason they locked my completely unused Microsoft account, that was created for the sole purpose of migrating my Minecraft account to, due to "unusual behavior" (or "activity that violates our Microsoft Services Agreement" if you go by the error message instead of the corresponding knowledge base article).

The reasonable thing to do in such a case if of course to require users to "[verify] [they] are the account owner" by receiving an SMS verification code on an arbitrary phone number (they explicitly mention the possibility of "asking a trusted friend or family member" for this).

[1] https://github.com/MultiMC/Launcher/issues/4093