Sounds like these parents have very unrealistic expectations. Especially at her age. Once a child turns 3, then I understand that they would want to really get potty training under way, but at 2 do they really think she will train in 3 days? Obviously they are first time parents who just have no clue. You are simply going to have to stick to your rules no matter how insistent they are. They can do whatever they want at their house, but your daycare YOUR rules. You could try to offer that you can take her potty at certain points during the day etc., but at the end of the day it's not fair to you that they just put her in underwear and have her pee all over your house.