I never assume the capacity of my crankcase equals the amount of oil I put in. My car came on a truck accross the country from a dealer in Florida and they had graciously changed, and over-filled, the oil before sending it to me. If I hadn't sucked some out I probably would have fried my main bearings!
Not only that but I just recently noticed they had also used the dreaded green anti-freeze (click here)
in the process of giving it "all fresh fluids." They probably used DOT 3 brake fluid, too. It's for all these reasons and so many more that I never let someone else work on my cars unless I have no choice.