You know, I saw a story on one of the morning news shows the other day about this very subject. They were interviewing people, and most felt they had to go to work sick due to several things. The number one reason was that they didn't have sick days, and couldn't afford to miss. Then they listed things like competition in their office, not wanting to miss out on a deal/opportunity, etc.
Sometimes people are contageous before they even really know they are sick. I went to work once with what I thought was my usual sinus "stuff" and then that night began running a high fever. It turned out that I had strep, so I'm sure I was spreading germs all day even though I didn't mean to. In Liza's case though, that man knew he was exposed to a serious flu, and should have stayed home.
Stacey