I also think a lot of people come in sick if they don't get sick pay. If phoning in sick means they can't pay the rent or electric bill or whatever expense has to be paid, that's a no brainer for them. They come in sick.

She may not have been able to afford to stay home, and having a coworker ask her at least ten times if she's sure she shouldn't go home would only add to her misery and discomfort.

You may find yourself doing the same thing one day (if finances are tight).