What if a ticket originally purchased prior to July 21, 2014, was changed by the air carrier after July 21, 2014?

If a passenger purchased a ticket before July 21, 2014, and the air carrier changed the original itinerary after July 21, 2014, due to an involuntary re-route, neither the passenger nor the air carrier are liable to TSA for the difference in the imposition of the revised fee.