http://ir.lawnet.fordham.edu/cgi/viewcontent.cgi?article=117...
Confidentiality is a an agreement between parties not to disclose information to a third party.
You are now talking about the unintended disclosure of confidential information.
Since you are not a party to the confidentiality agreement, it is impossible to enforce against you.
As far as insider trader, I don't suspect a random person who stumbled upon such data lawfully could be found guilty of any crime for using it.
Moving from an absolutely legal treatment of the problem to an ethical/moral one. What you want to happen if you were the owner of those documents?
Something to consider.