We had a good sick leave plan until it got stretched, and when certain people were in charge.
Some supervisors would call you at a random time during the day to see if you were at home.
One director decided unilaterally to make it mandatory for any absence longer than three workdays be justified at that point by a doctor's note. You had to get out of bed, go to the MD's, get a note and either bring it in then or fax it…and when you returned you brought the original with you. After that, just bring a note whenever you came back.
And if you ran out of sick time? You could burn the three other earned time offs, but after that, you were on your own. (Interestingly, after one of us staff people was dx with cancer burned off all her leaves and was then on unpaid leave, we were asked to donate our paid leave times to help a supervisor who was very sick and obviously not going to be back to work in time. While we were refused the ability to do the same for fellow staffers).
Union fixed those.