The expiration is news to me as well. I guess I lose myki cards too fast to have noticed.
In the unlikely event you get a ticket checker play the victim and mentioning that you've just got off the plane from XXX and weren't aware that it expired.
You will most likely make it to the station without incident
Or maybe not.
https://www.theage.com.au/national/v...23-p50t4g.html
Odds are you won't be caught, but for me, I'd just pay the $6 for a new one. Yes, annoying, but $6 every 4 years isn't a huge penalty.