Are there more successful attempts?
It would be difficult to enumerate successful attempts since, by definition, they would have been successful at not being known. :-) -- Marc
I once suppressed information about a troop movement underway in Iraq after a request. Troop movements are explicitly mentioned in the Espionage Act.
Such requests, and other requests regarding obviously illegal material, should go to legal at wikimedia.org or emergency at wikimedia.org at the Foundation rather than to User:Oversight, by the way. There is a whole bunch of people on the oversight committee none of whom are known to have security clearances.
Fred