Sane thing happened to me with a ticket previously purchased in 2004 but, in my case, I owed almost TWICE as much ......18 cents!!! I put it on my charge card, which, of course, cost more to process than the 18 cents!
It's interesting that the day prior to this transaction I DID NOT have to pay it, despite the identical routes, price of ticket, and all purchased on the same day in 2004. Go figure!!