Alluring, which is what girls are supposed to be, but not outrageous.
If it were white, it wouldn't be half as bad/good as some wedding dresses I've seen.
But I wouldn't be able to dance too close to her.
My first inclination if I were that principal, would be to let it go, but would've liked to talk to the complainant first to explain that a lot of these things were a matter of personal opinion to see where that would take us. I 'spect most of the problem arose with the girl's very nice shape, and if it were "Bony Barbara" wearing it, it wouldn't be a problem.
I also might have suspended her, but purely as a symbolic gesture... as I think the 1/2 hour at the end of the school day was, to placate the complainant. Maybe there was some wisdom in that "suspension" after all.
But I don't see why an issue like this deserved all the yipping and yapping and ki-yi-ing... which I have just done, too.
Terry