I heard a good presentation about this. They did it for a team at Google. But it was daily, and you weren't allowed to tell anyone else. You just didn't respond to any requests for that day.

But even worse, you could also be assigned the "liar" task. In which case you were supposed to reply to emails but give intentionally wrong information some of the time. But in that case you would tell people that you were the liar and that your answers aren't to be trusted.

It seemed like a good way to make sure at least two people could do everything and that documentation was solid enough that you could recognize when someone was wrong.