Dealerships do it all the time. Irritates me to no end. First thing on my to do list after a dealer visit is to get my vacuum pump out and correct the oil level.
Most cars don't have an issue with a little bit of overfill, but the Northstar was NOT one of them. With 7.5 quarts of oil in the sump, and meant to be checked HOT, a lot of them were overfilled. Once all that oil got hot, this started a viscious cycle of stuck rings and oil burning. All this according to a GM powertrain engineer. The Northstar was one of the first V8 to meet ULEV specs, and had the piston ring placed very close to the top of the piston. This eliminated the gap of unburned fuel that would get into that gap. Anyway this practice has become very common in modern engine design. It also required the development of more heat resistant VII's.
Since my Northstar days, I've trained myself to keep the oil level midway (or a little above) on the dipstick, and watch it very closely. Some cars, like my previous Mercedes have oil level sensors that can be very picky. Had it go off when the oil level was just at the LOW mark on the stick when hot. 1/2 quart solved that issue.
My advice, don't overfill.