I just tested doing this manually and it behaves as you describe. I suspect Mark is correct.
You would be better off checking for an emergency situation prior to putting an interaction into the queue, for example, if it's Attendant, you could either not offer the option to the caller, or provide a message. Simply dectivating the queue probably causes an error of some kind.
Of course, if it's the whole call center that closes down, then that is what Unplanned Schedules are for!
Emails can be handled in a similar way (perhaps replying indicating that the expected wait time will be longer than anticipated and then putting the email into the queue anyway?)
Webchats will require you to customize your Web portal.
HTH