I totally agree with that.
If I went to a body mod artist and asked them to do something for me that they weren’t comfortable doing legally or even if they weren’t sure they had the skills to do it, but they still tried it as a favour, and if they fucked it up, I would see that as my fault.
There would be an unwritten rule (or a signed waiver), that if anything went wrong, that I was responsible for it.
If I had to go to hospital for treatment, then,
“I did it to myself”
If the medical staff asked why, I would say,
“No bodymody artist would do it, because they are not covered by law, so I was forced to try it on my own”
Then I would ask the doctor if they would help with the next one 
A different scenario, but a couple of days ago, I donated plasma and there was a trainee observing the procedure; I offered him an opportunity to use me as a pin cushion to practice on as many times as he liked.
If he fucked it up, I wouldn’t have blamed him.
My offer, my responsibility!
Even if they had asked me, and then he made a mistake…No issues, mistakes happen.
People need opportunities to try things, that’s how they learn.
