I picked my brother up from the airport a couple of years ago. He too is a frequent flyer and had, at the time, a non-black suitcase. We grabbed "his bag" and walked out the door. About halfway home we got a call from the airline saying they had his bag. Woops. We turned around and went back to the airport. Sure enough, he had grabbed someone else's non-black suitcase. Color was similar but they looked sufficiently different to me.