I like Cathy A's line. Kriston, it doesn't sound uppity (and I'd know being good at uppity) but it sounds aggressive and might bring out the Negative Nellie's ire. My favorite all-purpose line is "It's all about fit between the child, the teacher and the environment." I've been able to use it about my child, other friend's children -- especially the "it's never going to be right" contingent, and children that I have taught. It puts the conversation into a blame-free zone.