I was 18 when I got my first mechanic job in a gas station. It was an independant SOHO in Akron. The first thing the owner did was teach me to rip off customers. That was in 1978. I did not work for him long not because of screwing the customer but because he screwed with my money. I would not do that stuff to day because its wrong.
The customer should be able to take their car into any shop and not have to worry about being ripped off. We all know that it happens and all we can do is protect our selves and our family and friends.
If your in the business all you can do is not rip off the customer. If you work for a shop that is not ethical find another job. If your an owner and are ripping off the customer YOU not I have to live with it and trust me the word does get around.