The police would give the woman a ticket if they spotted her without her child in a safe seat. You must feel torn in two a&b, worried for the child and want to do the right thing vs. wondering if you should mind your own business. If it were me I would talk to the Mom at pickup time by saying that her daughter said, blah, blah and ask her if there is a problem or if the child was mistaken. That might be a good way to open a dialogue. As far as what you say after that, well it's up to your conscience.