[mitoyarzun]

In Santiago, Chile, the public transportation system uses Mifare Classic cards, and few apps that (ilegally) refilled the cards appeared a while ago.

The solution given by the government was to block the cards that were used with fraudulent refills on a weekly basis, but there is always the possibility of changing the ID or purchasing blank cards.

Of course the system was chosen years after the vulnerabilities were discovered, too.

My guess is that the only way to stop this is to replace all the scanners, which will be far more expensive than losing a few thousand paying customers per day.