When you want to unsubscribe from the Daily Digg, you can simply go to this URL: http://link.digg.com/manage/optout?email=my@email.com
And manage the subscription for this email. So why not pull a prank and unsubscribe all Digg employees this way.
Let's assume that everyone on the About page of Digg (http://digg.com/about) has an official Digg account such as kevin@digg.com. We load the page and bam, unsubscribe. Hopefully we can raise some confusion at HQ. Funny enough, not every employee is subscribed to the Daily Digg, these guys were not: Jon & Jake, Shivram, Justin, David