Former Bungie, Pokémon lawyer explains how they caught leakers

This seems like a red herring. Sure, people often use the same online handlers for unrelated service (I do it too BTW); but people releasing leaks are bound to be a bit more careful.

If I was a business, interested on knowing who releases some critical internal information, I'd do it based on the leak itself. Who had access to that info? From that, an obvious consequence is to give each person slightly different bits of info, in things that don't matter for the project, like:

• if it's a picture, include an unique pixel of a slightly different colour for each person working with it. Make it #FE7A13 for one, #FE7A14 for another, #FE7B13 for a third one.
• if it's a 3D mesh, place some node in a slightly different position. Or change a single connection to another node.
• if it's software, make it so a specific key combination or set of actions show an unique ID of the build, and the build changes from person to person. etc.

I'm not specially smart when it comes to those things, so odds are that those businesses - specially rogue corporations, like Nintendo - already thought about it. And the idea is such a low-hanging fruit that they likely use it.

Also, if this guy is a "legend" for bullying a curious kid into submission... sorry to be blunt but he's simply an arsehole.