I have accepted many bullshit premises in manga before. I thought I was prepared to swallow anything if it's for the sake of comedy, but this somehow makes me riled up.
There are just too many arguments against this rule. But the one that really sticks out for me is Hanao's stupidity that translates into arrogance.
She is basically saying that she can avoid showing her privates no matter the situation and that everyone should be like her. The facts that she was reluctant to be president and her natural airheadedness are not enough to offset her aparent arrogance.
I hope that a glasses wearing boy that wanted to be the president(it seems fitting for some reason) flips her skirt in front of the whole school and teaches her a lesson on hubris.
Worthy of mention are the teachings of Chu-Bra! and other undergarment related mangas about the functional and aesthetical necessity of proper underwear. Also, even tough I have had the spirit of a horny virgin teenager since I was born and even after becoming an adult. I would still prefer to never see the pussy of the girl I like rather than everyone seeing it.
And finally, as an otaku I can't even fathom the idea of no more pantyshots. Panties have the perfect balance between pureness and lewdness. You will not take them away from me, you crazy woman!
BTW, I know I'm over-analyzing a comedy manga. But I couldn't sleep unless I got this ran off my chest. Maybe the romance will distract me from my distress.