If you know Elles real IG then you'll also know she posted a photo of her wearing this exact type of skirt for real a few years previously when she had to wear it every day. Makes me think she had experience of flashing her upskirt in real life.
If you follow her on socials you'll know she posted a throwback photo of when she used to wear a skirt exactly like this one when she had to every day. Makes you wonder, this must not have been the first time she flashed her upskirt.