Forging his resignation probably saved a lot of money for the company...
Ask yourself who had the incentive to leak that paragraph... And it sure as hell made me wonder why I had been "accidentally" sent the document in the first place.
edit: Worth noting, that this was a situation where the amount of money involved wasn't quite high enough to make it worth suing over. So really, it was just a dumb thing to do that didn't make any real difference - I wasn't going to realistically be able to get the money anyway. My best guess is this wasn't an "official" thing the client did, but rather a dumb spiteful mistake made by an individual at the company without the permission of anyone else, and who wasn't thinking about the situation objectively.
Crazy what people will do to just save a few bucks.
But... what's the motive? Just to be in a different legal position than firing this person (ie, avoid paying unemployment or whatever)?