@Naian When she goes around with her friends its not like they are the only ones who are gonna see her xDDD
And she getting mad when he sees her opening its like when a girl shortens her skirt so much that her panties show whenever she moves. Yeah, she gets embarrassed if someone sees them, but that isnt gonna stop her from shortening her skirt. Same with Megumi, she might get embarrassed but she still continues wearing every piece of clothe that shows as much skin as possible.
The autor use the naive or airhead cards to justify her behavior, but those are just different ways of telling she doesnt care. Maybe because she is too dumb to notice, but being dumb can also be a reason for a people to not care about something LOL