Graveleye,
The pony tail thing can be kind of scary because when you rappel, you almost always turn your head and look down. This puts the pony tail in prime position to get eaten by the rappel rack. But, not to worry. You can put your hair up into a panty hose cap on your head. You might find you'll want that or a bandana just to keep your hair out of the suspension in your helmet anyway. Even without, it's not that big of a deal. I let my pony tail hang, and I've never had a serious hair vs. rack experience. A stray hair here or there in the rack is painful, but not dangerous unless a significant part of the tail gets sucked in. The times I've lost a hair or two have trained me pretty well to keep some distance.
It's like Rescueman said, don't let anything distract you from safety and you'll be fine.
As far as the boobs in the rack goes, that sort of straddles the line between reality and urban legend and the whole thing is one of my wife's pet peeves. She wants to know, "who are these women?" and "How do you get a boob in the rack to begin with?" I don't think she'll be convinced unless we can see some battle scars.
Is this just a nipple issue or are there large amounts of flesh involved? Most women I know wear sportsbras when caving and would seem to offer some protection. Maybe Dave Bunnell sould offer some insight into this as he is somewhat of an expert in this area
All that being said; I do have rips in most of the shirts I use for vertical caving. Not so much from the rack, but from pinches between the D-ring and the metal attachments on my Fractio harness while ascending.
Sorry for the ramble, it's my day off.