I checked status of my demo account and got this:
"The e-mail address firstname.lastname@example.org is associated with the user cendsamu and the account is currently unavailable because it has expired.
The account expired 2013-07-05 UTC."
But I can still log in with the HTML5 client at https://eudemo.thinlinc.com:300. Connecting with the native client or with ssh does not work.
Similar to bug 4460.
Fixed in 28013. For things to test, see bug 4832.
Setting an account to be expired does indeed deny access through tlwebaccess. Closing.