#1 ignore it.
#2 inform your office staff that every movie they want is now available on click and play sites. There is no need to download anything anymore. Do these people still go to blockbuster to rent VHS movies? Jees!
#3 if it turns out to be legit, simply claim your office offers free wireless service and you are not responsible what customers or neighbors download. Do you really think McDonalds, due to their free wi-fi service, is paying out claims for copyright infringement?
Good points - Thanks