I've never had to deal with this, but I can imagine how frustrating it would be!

A friend if mine (didn't do daycare) ended up being the lady who watched everyone's kids in her neighborhood. The neighbor boy would come knock on her kids windows, making it hard for her to say no when she didn't want an extra kid around.

One day she saw her neighbors driving away, thought nothing of it as a set of grandparents lived with them too, until she tried to send neighbor boy home a half hour later and he came back because no one was there. She called his mom and apparently everyone in the house has gone for a "quick trip to ikea"!!! Unbelievable!