There is another effect that needs to be considered: the clean-room effect.
Consider someone working on a clean-room implementation of software. That person must be disallowed from viewing or experiencing the source code to a competing product. By viewing that code the developer may become in violation of copyright and/or patents that the original software contains. This is a serious concern in the software/hardware industry and shouldn't be dismissed lightly. Allowing the analysts to access the leaked data to may taint their conclusions when examining data.
So, to carry on with the barn door analogy, this is like closing the barn door after the horses have run away so your veterinarians and trainers can't go over to the neighbouring farm and see how the other farmer is training his thoroughbred racehorses.