Not quite Dave. In the first place if you are not a member (and if your music publisher is not a member) then the PRS has no title to your works and cannot charge you for using them. In the second place the great battle between U2 and the PRS was about the personal performance right, and it is possible as a result to withdraw from the PRS the right to administer the performing right in your compositions in respect of your personal performances of them.

And no, guest, what the PRS maintains (I think) is that the vast preponderance of performances of traditional song and music also substantially reproduce an arrangement that is still in copyright. They would be right as far as concerns the versions I (with or without others) do of Ramble Away, Byker Hill, and less directly Famous Flower of Serving Men - in an interesting place on Sir Patrick Spens, and possibly up a gum tree on Sailor's Life.