Casual/Drop In Care

Hi All.
I am looking for some input on casual/drop in care.
Let me provide you with the details of how we do it now, and then fill you in on the problem we are running into...
We offer wha twe call casual care for registered families who do not require full time care. These families must send us their schedules for the upcoming month during the last week of the current month. They pay per day and we do not offer any refunds if care is not utilized or if days are switched for another etc. We are sympathetic to the fact that things can come up and care me be needed on shorter notice etc so we have implemented a 48 hour rule-if they give us 48 hours notice their child can attend.
The problem we are running into is that even though they don't get refunds for days unused-or cant switch a paid day that they no longer need for an unpaid day we are still seeing a CONSTANT switch, addition or even cancelling of care needed. It's getting to the point where it's hard to keep track of all the constant changes and we are afraid we are going to send a child on the bus who was actually meant to be here (for example). I've even seen where I have a schedule and the child still just comes whenever, or just doesn't show up whenever even if said child is scheduled in.
We would like to continue to cater to our families need (we live in a predominately shift work town), but we need to streamline this process etc.
Any ideas? Does anyone offer casual care at their location? How do you "police" it?
Thanks for any input!

"The problem we are running into is that even though they don't get refunds for days unused-or cant switch a paid day that they no longer need for an unpaid day we are still seeing a CONSTANT switch, addition or even cancelling of care needed."

Charge in advance. They have then paid for the days as per their schedule. Then if there is a request for an extra day or a switch, staff can explain that a switch IS an extra day and that it will be approved once the extra day's fees have been received.
If fees not paid, then care is declined at the door because the child is not expected for that day.

Can I ask, you said that "I've even seen where I have a schedule and the child still just comes whenever", why is that child being accepted at drop off? They have not booked a space for the day. What would you do if you were at capacity and an unexpected child showed up?

Personally, I would do it so that :

1. Parent submits their schedule when due, WITH PAYMENT for the days they are booking.
2. If a parent requests a switch, then remind them that the policy is they pay for the extra day even if they don't intend coming for what they booked.
3. If they cancel a day, having been paid in advance simply means one fewer children. The policy that no refunds are given is again a published policy.
4. If they request an extra day, then that is only available if booked 48 hours in advance (as per your current policy) but must be accompanied by payment.
5. For this to work smoothly, you must have a list of expected children for that day, and you must meet children/parents at the door to head off anyone who isn't expected/hasn't paid. Lock the door so they can't just run in and call out and run off. Change the policy so that the door is locked and parents have to be admitted. A centre wouldn't have people just strolling in so this is a simple way of only granting access to those who should be there, have booked, and paid for the day.

When I did part time and casual, I required days booked by a mutually agreed upon day (often the 25th of the previous month) and I required payment and confirmed times each Friday for the following week. No refunds if not used. If they needed extra days or time, it was subject to availability (i.e. If I wanted to or if no one else was scheduled).

Where are you located (province?) and are you a home daycare or a centre?

You use the term "we" as if you are in a daycare centre. Is this the case?