It isn't because of being in the Middle East as it's happened to me too and I'm as far away as you can be from there. It's not an IP Ban either. You'll notice that if you clear your cookies and access from a nonsaved password you can browse fine. It only happens when you log into your account.
I have no idea why they do it though. Happened to me and I had never broken any rules. You'll also notice when you get back on there that there will be no trace of any posts or threads you made although your account will still be there.
I really do think they get bored. Either that or they Ban people that might be creating competition with files they are uploading.