Not to hijack the "Mighty Met" theme here. Artists have widely varying attitudes about bootlegging, and it spill over into how their fans react. The Gratefu Dead never cared what you recorded or traded. But a Deadhead collector got a rude awakening when he met a Zep collector. Peter Grant beat up so many record store owners for selling boots, they were rare and Zep collectors always demand something in return. I got offered $300 for a period LP of Zep's show in 1968 at Gonzaga. Pericles told me there are some clandestine sources where you can get a lot of Rush shows, I don't think the band really approves, but they are half retired anyway.
I felt a lot safer when Jimmy Page was photographed in a Japanese store buying a bootleg of his own band. I'm not a Met collector but their live shows are great.
Away from music, Gary Larson asked people to keep his Far Side cartoons off the internet...to this day it's still very difficult to find one.