Never work with children or animals, goes the old adage. Children have a crazy tendancy to do exactly the opposite of what you want as soon as a camera is produced. The adorable behaviour you were hoping to surreptitiously capture either dries up in a fit of sudden shyness or turns in to a hyper-self-conscious version of itself. Not so with children engaged in creative activities! When a child's attention is fully focused on the task at hand they become oblivious to the outside world and a complete delight to photograph. I would do this kind of work for free if I didn't have to eat.