Part of their scheduled talk, Anatomy of a Subway Hack, would have provided details in how it's possible to generate stored-value fare cards, reverse engineer magstripes, and tap into the fare vendor network. And I think it's reasonable to assume others already have figured some of this out.
Because U.S. District Judge George O'Toole has decided not to decide until next Tuesday, this story may not move forward until Aug. 19. The problem of trying to solve security vulnerabilities like this through the legal stifling of speech are manifold. Like the fact that it does nothing to solve the underlying security problems, and steals energy away from actually mitigating the problem. Chris Wysopal summed it up very well in his Zero In A Bit blog at VeraCode:
"Security problems go away by mandating independent security testing before a product is accepted, not by trying to get security researchers to be quiet. This is a good example of how the reactive approach doesn't work. The flaws are still in the system and suing researchers has just shined a bright light on them."
Wysopal is right, and if the energy used to stifle the MIT students from publishing their research had been used to test the payment systems before it was deployed, you'd be reading about something else right now. So if you're upset at these researchers for finding these flaws, your anger is misplaced: it should be directed at the authorities for buying such a sheep of a system.
The idiocy of this all, especially now, is that the student's PowerPoint presentation was given to the thousands of Defcon attendees, and a 5-page vulnerability analysis already has become public. Not to forget, as ZDNet's Richard Koman noted earlier, that the MBTA, in its legal compliant, put a 30-page confidential report written by the students into the public record.