Sadly it's the first thing to come to my mind with Sailor Jupiter. Which is why I just couldn't help myself despite the poor taste. I'm so sorry.
Honestly, I think it's the fault of the emphasis used from the scene when she mentions having the 'talent'. Then again, we didn't give a *squee!* as much back then about the implications. Ah, the good old days.
The age old trope of anime, girls worried about or emphasizing their bust in some way. Not that it doesn't happen in real life, but not as much as anime puts it.
It's to keep the wearer straight... I guess. Of course, the worst part is you're not allowed to have any Pepsi.