It seems that a lot of companies have had no problem admitting they got hacked in recent years and I think they could use that as an out, to free them of liability, if users were to discover their data was floating around out there and it was clear where it came from.

Also, I've seen numerous cases where companies will say their site was hacked when something is posted that makes them look bad. Let's not forget Steve Jobs' belligerent statements about Antennagate and BlackBerry's RIM.