Yes, I read about it on Cointelegraph. It is scary. Imagine you have a couple of BTCs and then your account gets banned. I don't know what had actually happened but Bittrex guys should have informed users before banning them.
the blocking can be opened , a friend of mine has experienced the thing you mean , have bitcoin but can not withdraw , it made my friend try to contact suports , the result the core of the conversation between them that my friend must be selfie using a piece of paper and I think it's fair , so many fake accounts there are only for deposit and withdraw not to trade
bittrex is now intended to allow genuine users instead of multiple accounts