She's Talented, That Girl

Ok, don't take this the wrong way, but I think that everyone can agree that such a hairstyle makes it much easier for someone to grab. I'm not meaning in a sexual manner, mind you, but for combat you'd have to be an idiot to wear your hair like that. Yes, she's a civilian, and you don't expect someone like her to fight, but if you think about it there has never been, nor will there ever be, a perfect society where violence and crime do not exist. At least a ponytail is located behind the head so it's easier to keep way from any threat you happen to be facing, but twintails can also block your peripheral vision if you incline your head. Furthermore, they just scream that you are unaware of the dangers that exist in the world. Maybe it's just a stereotype that naive characters typically use this style, or maybe I'm just reading too into it... Anyway, the point is, I think the reader subconciously recognizes this weakness as a sort of childlike innocence that deserves protecting on some level. That or they previously had a crush on some anime girl sporting it.

There's my two cents, at least.