Why does my 2.5 year old daughter uses the potty everytime at daycare but...?

not with me! She oly tells me sometimes that she has to go potty. At daycare she NEVER has an accident! I am getting so frustrated because the daycare teachers are telling me to take her pull-ups off and just leave her underwear on. Which i do until she has like 3 accidents in a row and then i end up putting the oull ups right back on. And they say i shoudln't do that, but what am i supposed to do?? Change her outfits until she runs out of outfits to wear and haveher pee all over the couches and the bed?? Why is she doing this?? Anybody experience something similar??