Agree on asking mom to provide suncare clothing and there are several lines meant to protect against sun rays, wide hat, etc. in the sense that mom needs to take responsibility knowing you are taking them out in the sun. I would also have her sign something saying that she is aware that you may be outside at any hour of the daycare day and that she does not want her child to wear sunscreen.

I don't put sunscreen on them unless I have to because I would rather they were not lathered in it every day either. We are outside from 7:30 to 9:00 and it is up to parent to apply sunscreen before coming if they want it used. We are out again after nap so after 3:15 and yard is mostly shaded. I will put on sunscreen after nap before outside if parent provides the sunscreen.