Getting people to stay home when they are sick has been harder to implement than you'd think. I've tried with my work team. A number of the developers are from cultures that have what I would call a very stubborn "must work at all costs" mentality. It can take some persuasion (berating?) to get some of them to see that taking a sick day doesn't make them a "bad worker," but showing up sick, getting other people sick, and pushing buggy code because they're sick does.