Totally agree. Even if they drop them off for a 1/2 day or something, instead of the whole 9 or 10 hours, that would be great. I did the same thing, in that I just took the time off at Christmas or whatever holiday break it was. I have had the same family be the only one that brings them for the entire holidays or whenever they had time off, so I was stuck with just those children.
I always was sure to mention to the parents, that "Oh, it was just them today, as all the other parents kept their kids home to spend time with them for Christmas vacation, or other holiday break...".