The short answer is yes, but not to the e xact second of the expiration time.
The background: in playing with the Trial app and in-app purchase sample, I tried setting the ExpirationDate for the trial license (in trial-mode.xml for Scenario 1) to a time that’s only a minute in the future. When running the app in Visual Studio, I expected to see a licensechanged event fired when that time passed, but didn’t. I could use the buttons in the app to check the license and see that it’s expired, but the event wasn’t there. So I wondered if this was expected behavior, or if it was related to using the CurrentAppSimulator object instead of CurrentApp.
Turns out that I just needed to be more patient! For sake of performance and reducing power consumption, the license time tracker in Windows does not send such notifications the moment a license expires. But the event will eventually fire, generally on the order of a few tens of minutes. So yes, your customers might get another half-hour of free usage, but those trials will indeed expire and the app will receive the event.
(Thanks to Sanjeev Dwivedi for the insight here.)