So no one had any advice for the OP.

I will give it a try. You could get rid of your paid vacation and raise your daily fees to incorporate the income you would have made over your holidays.

Or, I require two weeks notice of termination or two full weeks fees in lieu of notice. If in those two weeks they have days booked off or I have days booked off, or if they miss days for illness etc. it doesn't matter two full weeks fees are still do regardless of attendance or schedule. Do you have something similar and are these parents that are leaving before your holidays giving you notice? If they have to pay two weeks fees in lieu of notice regardless, then it would take their incentive for leaving to not pay for your holidays away? I don't know if that's coming across clearly or not?