Not so sure about Bittrex. They allow you to transfer coins in, but you need to be validated to transfer anything out. Lots of people are having validation issues (myself included), and the staff seems completely overwhelmed by the number of support tickets.
Me too ... I can't transfer anything in... always. Error messages
No answer to my support tickets in over a week...
I'm just over two weeks at this point. Something happened recently to their verification process that made it almost unworkable for many people. Likely a change required by the US government to link account holders to real identities. I don't think the support staff is able to deal with the flood of tickets that has resulted due to panicked (unverified) account holders trying to reclaim their coins.