The exchanges have repeatedly had problems with having their accounts containing user funds closed or frozen.  By now they should all have contingency plans for dealing with this issue because it's a foreseeable one and trying to fly under the radar when they adopt new deposit taking or payment processing methods does nothing to prevent it.

Likewise, users should also realise by now that if they choose to use unregulated exchanges there's a non-trivial chance that at some point they'll find access to their funds frozen because the exchanges have run afoul of either AML laws or the anti-fraud measures of the services through which they are channelling payments.

It's probably time that the exchanges explicitly stated on their websites that they cannot guarantee their users will be able to withdraw their funds "at call".  I'm quite sure that most people won't bother to read any product disclosure statements or expanded terms of service, but at least full disclosure of the circumstances under which users might not be able to access their funds immediately might cut down on the number of threads complaining about delayed withdrawals, additional user verification requirements, etc.