I stick by what I wrote and this is why

If the musician negotiates a fee of lets say £150 purely for argument sake and I don't turn up - then the musician receives £150

If I do turn up with two of my mates at £8 a head then between us we pay £24. Does that £24 go to the musician? No - it goes to the organiser and the musician receives £150

What I pay goes to the organiser not to the musician

The musician gets his fee from the organiser and there is nothing wrong with that. - unless of course you operate a system where the musician gets the gate takings and you get your money from the bar?