Something to remember too is that the overwhelming majority of play isn't happening at con's, so, it's probably statistically likely that a lot of the harassment isn't happening at con's either. With things like Encounters and Pathfinder Society, you have an awful lot of gaming going on with strangers on a pretty regular basis.
I have no idea what the actual numbers are, but, back around 15 years ago (the last time I saw any numbers) the RPGA had about 150k members. At a guess, I'd hope Encounters+Pathfinder Society is the same size. Again, I don't know, so, I'm going entirely with my gut.
But, in any case, there's a boatload of strangers playing together in public spaces on a regular basis.
So, the issue of harassment has to be handled at the "grassroots" level as well. FLGS's need to make it abundantly clear that harassment is a thing and it's not tolerated. Clearly post harassment policies in visible places, heck use the Encounters policy and just blow it up to poster size, in the gaming store. The store managers should also probably take a few minutes at the beginning of each Season, to sit down with the DM's for a few minutes (it's not like this takes hours to make clear) that harassment is being taken very seriously and the DM's should be both alert for it and conscious of it when running games.
Organised play, IMO, is a good place to disseminate information and educate people that this sort of thing is totally unacceptable.