And I do agree that I don't think that miniskirts are appropriate for girls who are young enough to play on the playground. I think that high fashion trickles down to young girls much more so than to young boys, and that clothes that are appropriate for adults (or not, I don't really care) are NOT appropriate for kids who need to be able to move freely and run and play. I can't tell you how many young girls I see at the playground in little slip-on ballet flats or flipflops that they can't run in, in super tight skinny jeans that don't allow movement, in tiny miniskirts that they're constantly tugging down. I don't think that it's appropriate for kids of either sex to show underwear, but I can't say that I've ever actually seen a boy doing it. They still get to run around in sneakers and jeans and oversize t shirts. It's not even entirely a "modesty" issue, it's also a practical one. Those clothes just aren't practical to play in. You can't go down a slide in a miniskirt that rides up: your butt won't slide down the hot metal slide easily.
She also goes to the playground after ballet sometimes, weather permitting. That means she's wearing tights, a leotard, and a ballet skirt...but not her ballet shoes, because she doesn't want to get them dirty.