The fact that the child was obviously cold definitely warrants talking to the parents and ensuring that he at least packs an extra sweater that can be put on when he is with you. My 5 year old complains every day about the layers I put on him to go out to school, but for me it is not something I will compromise on. The kids have to play outside at recess unless it is colder than
-25 at my son's school....so they can be out for half an hour in -20....they need to be dressed warmly.