"Thou shall not rip off revival singers - though it doesn't matter too much with source singers".

Jim, I think you've misinterpreted SO'P's meaning there.

As for myself, as stated upthread, I did rip off a handful of 60's revival albums last year, simply in order to hear renditions of traditional songs - so I could learn some myself.

I thought of it as err akin to 'borrowing' the songs from those who had recorded them, pretty much in the same way that revival singers themselves had done so from source singers.

I must confess that I didn't feel terribly guilty about it.