Here's what I want to know:

Often on CD liner notes I see that there was a musician from outside the band who played on the CD, and the words, "Musician X appeared courtesy of Record Company Y."

Courtesy of? Does this imply that musician X had to beg - or buy - permission from some record company to play on another band's recording?

Why doesn't it say "Musician X appeared courtesy of his own band", or maybe "Musician X appeared courtesy of her ability and willingness to collaborate with us"?

Thanks, Marion