Help Me with my NEW Sick Policy

[mom-in-alberta]

I have 4 paid personal days (in addition to stats and 10 days vacation). I reserve these days for when I (or my children) are too sick to have the daycare open.
When interviewing a family, I discuss this policy. I let them know that the reality is, with 4 kids, I MAY need to take an unexpected day off. I avoid this at all cost, but it happens. I also have it in my handbook that if their child is sick, they still pay regular fee. If I call them and give them the option of keeping the child home, and they choose to, they still pay regular fee. If I call and TELL them I am closing, then I will put that day down as a personal day.
I will make exceptions, in certain cases. The other day, my son was throwing up in the night. I had a p/t due, and called them in the morning to make them aware. I told them that I was fine, but they chose to keep their little guy home. They now have a "free" day to apply to the remainder of the month or to next month, since they pay in advance on the first.
People have been pretty good for this, thankfully. I think I have a policy that is fairly kind to me, haha, but I take the approach with parents of "putting the shoe on the other foot". They wouldn't appreciate having someone else bring their sick kid! I do have a 24 hour rule (no vomitting or runs), but it is very tough to enforce that.
I would definitely be cautious when dealing with this family. I would bet money that if you keep them in care, this is only going to be the first of many issues. Could be wrong.... but it just seems like a warning sign. I don't know if I would say or do anything now, but in future, they would be on a short leash!!