I agree. When I pulled my rims to have the tires changed, I brought the rims only. I even pulled the center caps. Manager gave me a funny look. I returned a 1/2 hr later and there was the same elderly couple that had been sitting there all day. I shot the same Manager a look of "why-the-^&$ are those poor folks still here?" then he couldn't look at me in the face anymore.
I seriously have difficulty when people just "bring it in" ..like my brother ..that got charged $135 to change an idler pulley. Yeah, buy a book, join a forum, talk to an old wrench monkey, do whatever it takes to stay the heck outta those places.
As for the brown stuff, slow your roll broseph primem, lol! It really is too bad the guy got bad service, but it's past that joint now. It's not a huge deal to have all that nasty crap still in there. I did LIMs on my 1997 Blazer, flushed again this year and there was still junk coming out in chunks. I know for a fact the heater core on that's going, but the two older (97&99) GTP's I've owned both had similar results. I never did do a "clean" on any of them. But, I just found out my GP is 1 of 3,009 made, and I don't know how many in this color. Better believe I'm doing it in this car.