Depends on what the NDA says. I'm not 100% positive but my understanding is that since it's a private contract you can't be thrown in jail. But the club could go after you for damages, say if you said "they're going to buy this location" and then the land owner raises their asking price they could try and blame you.Ah so its serviced by the N D & A trains. Well done sir.
Anywho, whats the penalty for breaching an NDA, fine or jail time?
More realistically they might just never ask you to participate in something like this, extreme case - they revoke your season tickets. Though if they did the latter or brought any legal action against a fan it would be a PR disaster for them and CFG and I don't know how many more of those they want.