Well I know that the london underground system also uses Mifare and the Oyster card designers know about the hack.
Their problem is that all other chips which use a better encryption are more expensive.
I think each oyster card costs about £4.00
They give them away for free when making ticket purchases and they make the cost of card back in profits over time in use of the card.
So at the moment I think they are just treading water to see what happens. Its a dangerous situation.
They have had many meetings about the situation and have been investigating differing options regarding costings etc.
It would be possible to carry out a sort of money loss program on a company with this business plan by applying for oysters and not using them each one costing the company £4.00 of total profit loss.
It would take hundreds of thousands of users to make it even be noticed though. TFL (Transport for london have very deep pockets).
So as far as Mifare and RIFD hacks go, Mifare is a cheap chip that because of the cost is unable to use decent encryption. I think that to get better encryption then the possible profit loss per card increases as does total time to make profit on each card.