Yep, I've had that happen with a private outlook.com account last month. I literally just created the account and used it just once, to register for an Azure ce

Yep, I've had that happen with a private outlook.com account last month. I literally just created the account and used it just once, to register for an Azure certification exam. I sent no e-mails from that account, I just checked it twice or thrice for incoming exam information emails, until suddenly I could not log in because of ToS violations. Stay classy, Microsoft!