My daughter is 6 and still has tiny accidents, she's busy or lazy and races to the bathroom too and has a dribble or two in her pants but mostly goes in toliet. It frustrates me beyond belief. Usually I will have asked her 5min. beforehand if she needed to go. And she usually tells me oh no mommy.
I make her 100% in charge, she knows the drill and is so good at it sometimes I don't even know she had accident unless I notice soiled panties soaking or she changed her clothing.
So I force her to go sometimes. If I know she hasn't gone in awhile and she most likely is being lazy I'm like to bad go up stairs and try.
As far as running a daycare I'd leave the mess up to her except for the chemicals to clean it up. Maybe you could make her go every 2 hours regardless or she has to atleast try every 2 hours. Is she doing this at home too or just at your house where she's busy with all the kids?
If she's borrowing your clothing or your spare clothes make it something not fun to change into also.
*Although keep this in mind, when my daughter was 3 and had been potty trained for awhile and would have 3 accidents in one day I took her into the doctor. I thought my goodness there must be something like a bladder infection. Well they did a xray which I thought was weird and it ended up my daughter severely constipated which meant everything was pushing on her bladder. So there was a medical reason for her many accidents out of the blue, with a prescription to help her go #2 she stopped having the accidents like that!