Yeah, every dealership is only as good as its worst employee is the main problem. Ive been to many, and truth is there is a chain of people in the process of servicing your car or truck. You may have a great salesman, but ****** service manager, or you might have a great service manager, and a ****** tech...etc. etc.
To the OP, not only is that common, but I have a great personal experience for you-
One of my best friends had their '03 Cobra in getting serviced, and not only did the tech take it joy riding, but then took it to a whole new level of stupid by going on SVT forum and bragging how he ragged the car out and got it up to 130+ mph...problem? The owner is a member of that forum and read that post. He did transmission and engine damage to the car, and the dealership abruptly ended his employment, and had to pay all kinds of money to get out of that mess.
I had a tech with greasy hands installing my lightbar on my Shelby with 3 miles on it. I FLIPPED OUT!
I had another "SVT Certified" tech ask me if my Shelby was suoercharged....while the hood was opened, and if I thought to change the tune for a supercharged engine. After I got done pointing and the laughter died down, I got in and drove away.
Neither dealership gets to touch my cars anymore.