I've been hesitant to post because I was worried about the response that I might get back. But here goes. I can't help but completely understand where the mother is coming from. When my daughter was 2.5 years old, she was at a daycare that had the same policy around wearing pull-ups. When we first learned of this policy, we were completely ok with it. That was until it was time to actually potty-train our daughter. My husband and I would get so frustrated because on weekends when we were at home with our daughter, she wore underwear and was accident free. But at her daycare, in pull-ups, she was not. We too believed that it was because she couldn't distinguish between diapers and pull-ups and almost felt like she had "permission" to pee in her pull-ups but was very conscious about not doing so when she had underwear on. We couldn't take two weeks off from work just to potty-train. We really did need the help and support of our daycare provider, but were on separate pages when it came to how to train her. We ended up having a heart-to-heart with our provider and she agreed to a 3-day trial where our daughter could wear underwear except for naps. It worked!! She was accident free and was allowed to continue wearing underwear. That experience has made me realize that every child is different and what might work for the majority of children, might not work for all. Anyway, I guess I just feel that occasionally we need to entertain the idea of making exceptions. But this is just my personal opinion.
That's where the, wearing the underware with a pull up over top comes in. Th child feels the underware and so therefore less inclined to pee but if she pees the pull up is there to catch it for the caregiver. Win win for all.