It gets worse.
I'm a bit of a jazzer as well as a folkie.'Trad'(Am.'New Orleans') jazz mainly.Much of the trad jazz canon is not actually traditional,the composers are well known and venerated-W.C.Handy,Clarence Williams et al,no longer around,but recently deceased-e.g.WCH 1958 less than 70 years ago therefore estate entitled to royalties.
So,no bee in my bonnet about PRS collecting royalties via annual'licence'fees from pubs putting on a trad jazz band of a Sunday lunchtime.
That is,until I read the Pavane's list of American public domain work.Many of the big trad numbers are there-e.g.St.Louis Blues,High Society,Royal Garden Blues.
Does that mean PRS are collecting for US composers under reciprocal arrangements when the yanks aren't actually interested in having the dosh?