They still can't talk about it. First the court ordered three M.I.T students not to present their findings on how to hack the Boston subway/ Massachusetts Bay Transportation Authority (MBTA) system fare system. So no presentation happened at Defcon on it as a result.

Instead the full presentation ended up being posted publicly on the internet for all to see. Yet still the court order restricting the students from actually talking about the flaws is in place. The AP reports that:

Judge George O'Toole Jr. also ordered the students Thursday to turn over more information about their findings, including a report they submitted to their professor - cryptography pioneer Ronald Rivest - and computer code they planned to release as part of their presentation.

A hearing is scheduled for Tuesday to determine the next steps. The students claimed that they disclosed issues to the MBTA first but considering the backlash, I think it's safe to assume that the information (at least not all of it) didn't get to the right people.