I am surprised that guy acted like such a douchebag. Most just do not care, and just think evil things about the elderly and disabled.
During a time when I used a wheelchair most of the time, I went into a store with my mother. I was using crutches that day. After putting a few things in my cart, I headed to the register. There were two people in front of me. The one going through checkout looked back and decided she needed more stuff. So, off she goes. Then, she needed price checks. Before she ever paid for her stuff, my legs collapsed, and I could not hold myself up any longer. Nobody cared at all, except for two employees at the store. Everyone else looked at me like I must have been some sort of mental patient. One employee stayed with me, while the other got me a chair. Since then, I have walked out of stores without buying anything if the lines were bad and if I was in ANY pain, or if there was only one register open.
Some people just suck, and others are worse. We can use a few more angels in the world.