Always lots of stories how dealer techs screw up oil changes. I'll bet not one customer considered asking who was doing the work on their car or their credentials. I was ignorant when I was young too.
You buy the second (or the most) expensive asset in your life yet don't care who's maintaining it? I'm not sure how it's done now, but there used to be three classes of technicians; A, B, and C. C's were the oil change/tire guys, B's were experienced mechanics, and A's were the best. They passed multiple, if not all ASE tests, and they were trained by the manufacturer of the brand. Any dealership I use, one tech does it all so I don't know if there are techs that just do grunt work anymore.
Not only do I make sure I get a top tech, I do my best to use the same tech every time. If it's an emergency and he's not there, I make sure I get someone he recommended. Also, I figure if I can afford a $45K out the door car I can afford to tip well.
So if you don't want to at least spend the amount of time researching a technician as you did when you were buying your car, I don't feel sorry for you.
And before you drive away, look at the area(s) that were worked on with the engine running. If you have an oil leak after an oil service it should be obvious. One thing to note is, the dealer is not supposed to reuse the drain plug.