Making predictions is difficult, especially about the future.
Saying you accidentally hired people makes it sound softer than it really is. If Raytheon or Boeing hired 2,000 people ahead of a defense contract they were sure they'd get, and didn't that wouldn't be an "accident." That would be poor planning (counting your eggs before they hatch kind of thing.)
Either way, I don't really care either way about Zynga. I don't think I've ever played their games, but at the same time I'm not hoping they fail.
Now, getting people and teams transferred once they are hired? That's a whole different story.
It's also very backwards (government-level!) thinking to be playing the hiring quota game like that. I'd much rather hire a few members in a kick-ass team than participate in a headcount battle.
That's not a mass redundancy, that's a mass replacement.
I could see two people both hiring a janitor without realizing it, but not "accidentally" hiring a lot of developers, designers or whatever else.