In order to have standing there has to be an actual real-life situation, not I'm afraid a boy might see me in my panties someday long into the future, which she will take off for him willingly given another year or so.
If a woman's boss came by their desk every day & said, or posted in the lunch room
"at any time in the restroom or company showers I can expose myself to you or other male employees can too", that would be standing for the woman to sue for sexual harassment. But you're saying if it's a minor girl in a locker room at school or showers, she just has to take it?
A young (or any aged) woman gets to choose when and where and with whom she takes her panties off in front of a male. That's the law.
Unfortunately, the law here in California is now otherwise. It's common decency, though, that it is entirely up to a women which males she will allow to see her in just her panties, or out of them; and by any rational standards, to deny her that element of consent amounts to sexual abuse.
Perhaps
JumpingPete sides, as he does, because that's the only way he has any hope of getting to see a woman undressed; surely no women would ever give him her consent willingly. Any precedent which denies a woman that right to withhold her consent is to his perceived favor. His implication that
“… she will take off [her panties]
for him willingly given another year or so.” is also rather telling, indicating a general contempt for young women, and an assumption that they are mere sluts who, in time, will gladly take off their panties for any male pervert, no matter how creepy.