If a song is trad, the person from whom it was collected, collected it at some point from someone else, who was more than likely also uncompensated. Trad./unknown composer tunes and songs are fair game. I agree that it goes both ways: A lot of those collecters were patronizing and greedy SOB's but, in the end, they're still the main reason we have access to the music.

Original compositions, on the other hand, ought to be compensated, and no quibbling about arrangements, etc. A lot of comparatively unsophisticated people got royally ripped-off.