The Safelite guys make 8 bucks an hour. That pretty much says it all.
I don't get outta bed for 8 bucks an hour.
Probably not a bad idea, especially since such parts can be hard to find for our cars. And stuff *can* happen, just like in any type of work. Slip of the extractor and ya got a nerf somewhere. Better safe than sorry.
As for watching, a lot of shops won't let customers into the shop area for insurance reasons (I mean, there are crates and sheets of flat glass standing around). Folks come into our shop all the time, and watch me work on their stuff. Doesn't bother me at all (they even ASK me sometimes if it bothers me, I shrug and say "no, of course not"). They're just interested, because glass is an almost esoteric field for most people.
Of course, other people are different, and some are fed up with the hand-wringing know-it-all type customers that are part of dealing with the public, and as a result won't let any customers anywhere near them while they're working.