In response to your original comment about how the daycare child soils herself at pick-up time - maybe you get him/her completely ready to go, (dressed, coat and boots on, backpack loaded) and wearing a pull up- just so that you can hand him/her off without the added delay of a change ? It sounds like you're already putting in a long day - the pull up shouldn't undo any potty training progress that they've made so long as Mum or Dad takes it off right away when they get home.