Open Letter to VidCon
You don't think you need a harassment policy?
http://www.ccfinlay.com/blog/so-i-asked-vidcon-for-a.html
Take a look at the other cons. Arisia for example has a code of conduct, and they take it damn seriously.
http://2013.arisia.org/code_of_conduct
Being the hot new thing doesn't make it a good idea to ignore the wisdom of those who've been doing this longer than you have. VidCon is getting a nasty reputation as the meat market for predators, so unless you want your attendee list to look more like the "Serial Convention" from "Sandman" than Comic Con, pull your heads out of the sand and take a good hard look at the problems your convention is facing.
Note: Comic Con has a harassment policy too:
http://www.comic-con.org/cci/convention-policies