I haven't really been asking, but the fact that I haven't heard anything bodes fairly well. It's still early. There's also some other elements at play regarding when female performers get assaulted during the event. They're all stupid, misogynistic things, but people can be stupid and misogynistic.
Accessibility - It's women on the street, who are in arms reach, that are targeted. When they're on a stage or stilts (see Festival), they're essentially safe. Or at least less likely to be harassed.
Recognition - If the performer is playing a known character, like Carrie White, Regan, or Chance, they're more likely to be targeted. Whether that's because the notoriety makes them less "human" to douchebags they want to pump themselves up going after a "celebrity," I don't know. For example: plants will almost never get assaulted because they look just every other guest. And assholes won't target another guest.
Weapons - Yep. Give a scantily-clad performer a weapon, even a fake one, the chance they'll get attacked drops dramatically. Even its something that could be USED as a weapon, like a staff or cane.
Attractiveness - The women who work at HHN are gorgeous. Objectively. That's a big reason why they're targeted. Throw a mask or a lot of blood on them and douches are much less likely to go after them.
Witnesses - The Grady Twins hold hands the entire time they're performing. That is their protection, 100%. Pairs work. Even in Vamp 55, the female vamps ALWAYS had a guy vamp at arm's length.
What I've noticed about this year (and last year, to an extent), they're doing a much better job of letting the women protect themselves with these sorts of tactics. The biggest issues come about when a pretty girl dressed a popular character is left alone. Universal has gotten better, but there still be issues. It's just waiting for them.