Harry Fox(AFAIK)only collects fees for mechanical licenses. That's if you record someone else's song for commercial purposes.
This ASCAP/BMI stuff has been going on for so long now, that it may start having it's own category in Snopes. There is a lot of mis-information out there about the fees, how much venues have to pay, who has to pay, what kind of music is exempt, etc. The house concert exemption has been the first step in dealing with the PROs and I do hope there will be more ground gained in this area.
I am NOT being an apologist for the PROs by any means. But because I don't perform "original material" I have a lot of doors closed in my face, even when I let venues know that I can *in confidence* perform ALL public domain material. The venues should be paying PRO fees, period. Small non-profit venues either should have the fees waived or be charged a much smaller rate than a large capacity bar or restaurant or concert hall. That has been the bone of contention with the fees and I do believe Folk Alliance has been addressing this.
But a venue that says "original music only" isn't really getting around paying the fees; just putting off the inevitable.
What it boils down to is venues being educated and knowing what their rights ARE where the PROS are concerned. There have been some good suggestions made above and I do know of many venues who were able to negotiate with the PROs for reasonable fees that fit the type of venue they are. I do agree that the PRO's tactics in some regions are pretty awful and the payment of royalties to artists in our genre is abysmal (Chuck Brodsky has A LOT to say about this).
If you take a look at the archives of the Folk Music discussion lists (Folk Alliance, FolkVenue, FolkBiz, even Folk DJ-L) you will find that a lot of bandwidth has been used over the years discussing this issue. If you find a posting from Mark Moss, Joel Mabus or Tom Neff, pay attention. Them's knows of which they speak and I have a lot of respect for any of those three when they write something.