If you're talking about public leaks (rather than just private leaks to a few individuals), surely they're not that hard to find?
I wonder if you mean the leakers?
(for the record, I'm a moderator of a forum which discusses said "leaked builds of Windows"; and I help try to find and preserve those that leaked long enough ago such that they have almost disappeared)
Surely if the "leak" is the result of an employee acting unlawfully, i.e. maliciously leaking their employer's intellectual property in contravention of their employment agreement, then the leak does not constitute a disclosure.
If it did, then IP-based organisations would have an absurd level of exposure to the bad actions of any employee, and would have to impose equally absurd security measures - cavity searches at the exits, anyone? - on every employee with access to IP.