That said, I even caution against judging other people for their use of a disabled placard without an apparent motion disability. I had a friend who had nothing obviously wrong with him (I was friends with him for about a year before I even knew he had a disabled placard), but one day he gave me a ride and apparently felt the need to explain to me that he has MS, and that walking was quite painful for him even though he moved with an apparently normal pace and gait. Presumably there are many other reasons why an otherwise normal-looking person would have and/or use one of these placards, so I really think you need to come in with more than anecdotes about people who don't seem disabled.