Yes, is relative to deadline. I think this work out of box with one statefull session that doesn't close (as in jbpm-console). But in real application, the session should be close in time, and then reopen.
In this enviroments, the "deadline event" when is shoot? Must a programmer open a session and check the date? If yes, is tedious. I like that timers in general must be work out of box. Timers are used in general with human task.
Juan