Most inspection stations don't really want to be in the business of state inspections. There isn't any money to make on them, and so a lot of places do use them as a loss leader. At my last job we did roughly 10,000 state inspections a year. By law we had to sell the stickers at cost + tax, so the state makes all the money on the stickers. After 10,000 units, we still lost money on have a station license in a year, if you just look at the cost of the labor for the inspection.
I personally didn't mess around with certain things that were in the book. Seatbelts I would make sure were not damaged, but didn't look farther, because if someone actually used their seat belt they weren't waiting for someone to fail the car at inspection to get it fixed. Same with parking brakes. What does it matter if it doesn't work if the owner (90% of them) doesn't use it? They will just get mad at you for failing it. The people who do use it won't wait to be told it doesn't work before getting it fixed.
The place I go now I know I am paying 2-3X what I would pay at some other places for my annual SI/EI checks (price never seems to be the same twice there) but I also know they aren't screwing with me. I know the guy who owns the place, and his head tech. Every time I drop a vehicle off for SI the conversation goes something like this...
Owner: How are you today, dropping off for SI?
Me: I'm good, how about you?
Owner: So is there anything wrong with it?
Me: Nope.
Two hours later on the phone:
Owner: Come pick it up.