The most common, is from the amount of oil that drops into the belly pan when the oil filter is changed. If the dealer did an oil change, that would be my guess.
If they have pinpointed it to a spot on the engine, then that would be rare. Based on it's location, and the amount that always spills, I would still blame a filter change. The other is the drain on the bottom of the crankcase has a crush washer on it. If they used a kit, they may have added a washer without removing the first. Two washers will cause a leak many times.
Good luck, report back what you find.