Forget free hotdogs; how about a free season ticket?
The main worry I had when I first started looking into it was not really so much to do with the possibility of nabbing free credit to use to buy drinks/snacks, but the fact the same cards are used for season ticket subscriptions. This being the case, you could theoretically clone another season ticket.
Also, with regards to the cloning of cash; the organised crime benefit would be that you are able to withdraw 'unused' cash from cards. If you cloned cards then withdrew the money, you could basically use the club as your own personal ATM...