No need to jump on my back. Maybe I could have put my thoughts into words better, I wasn't excusing any kind of harassment but pointing out unwanted attention should be expected. I get the feeling these incidents at cons are pretty rare.
Not as rare as one might hope. I had to convene an emergency 3AM meeting during a con about five years ago when we got a report of a sexual harrassment. (The person's membership was revoked following the meeting.)
The thing is, I think that probably a significant percentage of incidents get brushed off by the person on the receiving end as part of the environment of fandom, and so we never hear about them. I want to see that attitude stop. I want people who feel that they've been harrassed or assaulted to come and find a committee member, and tell us about it, so that we can do something about it.
I admit, I've done things at cons that some people would probably give me the side-eye about - but I only do it when I know the other person well and know that they'll take it in a playful spirit.
For instance: I have a friend - who's straight, with a girlfriend (whom I have known longer than I've known him) - with whom I have a ritual. Whenever we see each other, we hug with one hand, and grab each other's ass with the other. Someone who didn't know either of us might see it and think it was a situation where unwanted contact was being made. For us, it's just fun (he's actually complained when I haven't grabbed him - and one time, when he used the wrong hand and grabbed my wallet, he made sure to switch hands and grab the other side

).
I wouldn't do that to someone I've just met, of course. (Okay, I admit to that time at DragonCon, four years ago, when I started making out with a guy at a dance. But in my defense, we'd been hanging out for three days at that point, his roommate - who'd introduced us - was one of my Fairy Godsons, and we dated for a year and a half after that, so obviously he didn't mind toooooo much.

)
Organizers really can't police everyone.
They are expected to hold an event that is safe for everyone to attend. So yes, they should be policing and taking care of situations like these. And they should have policies in place that deal immediately with people who violate the law.
We do our best, but as Sir Humphrey Appleby once put it - "CBE, Prime Minister. Can't Be Everywhere." If we get conflicting reports, or there are no reliable witnesses, it's hard to do anything about it.
I haven't read the whole thread, just skimmed it since I have so much to catch up on. But in case it hasn't been mentioned, it's difficult to find non-sexy feminine outfits.
Make your own!

It's a lot of work, but judging by my costumer friends, it appears to be incredibly rewarding. (And I have one female friend who has built her own Stormtrooper armour - which is the antithesis of "sexy". Unless you have a very odd fetish.

)