As my Uber driver offered to put my suitcase in the trunk, he said, no obligation. I’m not sure what he meant. Was he saying that I didn’t need to tip him because he put my bag in the trunk? No idea. He said nothing else on the ride that implied he was providing anything beyond the basic service. Once you’re in an Uber, there are no levels of service. It’s not as if the driver is upselling you for a deluxe service level including champagne wishes and caviar dreams. And most people don’t tip Uber drivers regardless of what they do. But when we arrived at the airport, he got out of the car, opened the trunk and said no obligation again as he removed my bag.