I used to work at a shoe store.
A lot of my best customer service experiences were selling shoes to people with prosthetic feet. I saw it as a fun challenge.
Here was a (usually or relatively) immobile, plastic foot, so I had to find the right fit when the rules were completely different; they can't wiggle in, and the shoe won't stretch much.
I don't know if my coworkers purposely ignored them, or just gave up on them, but I never saw anyone else close a sale with a person with prosthetic feet.
The best was when a guy got stuck in a shoe, we couldn't get it off, so he just removed his leg and pulled it off. It was hilarious, I'm still laughing.
Disabled people have money, too. Treat them like any other customer, and SELL THEM THINGS.
You can't "catch" paralysis or amputated limbs.