Whilst taking my daughter to nursery this morning a nice looking bubbly blonde lass came out (no pics) said hello with a smile and breezed past me. I done the customer glance at her behind

only to see she had tucked her skirt into her knickers

I didnt say anything to her but I have told the story to two people this morning and both said "why didnt you tell her?"
How do you broach that, "erm sorry love your knickers are showing"