I do get why a -school- might have rules in place as far as how revealing a prom dress can be, and they took it pretty seriously if they had a contract in place to enforce the rule.
If other girls were made to cover up, and not just this particular girl, then fair enough, IMO. Even if they looked nice, they had signed a contrect with the school and knew what the rules were before purchasing the dresses.
However, as a fellow rack-owner, I feel for the girl in question. It's hard to find a nice dress which fits both bust and waist (well-fitting clothing for the hourglass figure went by the wayside in 1959, methinks..) and harder to find one that doesn't make you all Hooty McBoob.
I'm guilty of multiple charges where choosing a slightly smaller size is concerned, because it's easier to rein your hooters in than it is to deal with the baggy middle part when the waist and chest aren't anywhere close to the same ball park in size.