If you are charging them a full fee for the week then she is technically entitled to bring her child all 5 days. The fact she "normally" only uses 4 days is a bonus to you. In this case she is in her right to bring the child on Thursday instead of Friday if she wants to.
See, this is something I couldn't figure out - whether I was being rational or not. Problem is, I only take four kids on any given day. I will not always be able to accommodate her on the Thursday. So, how do I word this?
Always ensure that your child receives quality care by taking the time to investigate the provider and by asking for references! We simply cannot verify the claims of every daycare provider.
Updates
We expect providers to keep their listing and available openings up-to-date. However, to prevent oversights, openings expire after 45 days.