What the...

Ok, so my friend had quit for the past month at least. He logs on today, and we exchange hello's and all. He makes a comment, "Whoa, it's been 8 days past the expiration date, and my NX hasn't expired." I simply reply with, "Lucky...". So we go on and he wants to find out what's all new in MS, so I decided to take him to Singapore, since that's the only thing that hasn't been craptastical since he left. We're having fun and we're exploring. Suddenly, he is sent back to town from no where, and a ban message comes up on his window. He's all angry now.

Does anybody know why this happened?