Yes Sir you are absolutely correct except you did not mention the biggest oil change scam - "your transmission fluid needs changing............" and then you drive out with a $200+ oil change and a transmission likely to fail pre-maturely. Pisses me off to no end when they do that crap and actually I started using Walmart for oil changes at one time because they do not do transmission fluid so I did not have to cuss them out everytime like the oil change shops. But Walmart got otherwise too difficult to deal with so now found a new place and told them to put in the computer under my account - this guy is an ass and don't mention transmission fluid or other upsells to him- guy said they would note it and have not yet had a problem. All Crooks - and yes the dealers too!
I went in for an oil change once, they tried to hit me up for a tranny fluid change, I said, you do realize my car is a stick right...... He just looked at me and said sorry for the mix up