However, the songsmith is worthy of the few coppers that the PRS typically recover when his song is performed. I am ashamed to think that any folkie would take a stand on behalf of evaders of the PRS levies.

Investigation by the EFDSS some years ago proved that PRS returns for all but the largest venues - many festival concerts would not even qualify, are basically chucked in the bin. The PRS fees from all the smaller venues are apportioned as per the returns from the large venues. This would mean that if I make a return for singing a Cyril Tawney song in a folk club, the fee would quite likely go to S Club 7.
If I were to sing a traditional version of Scarborough Fair in a large venue, Paul Simon would get the return. PRS provides very little benefit to any folk authors.