Is it wrong to use an amputee as a prop?

This is similar to a previous question I asked, but different. There's a couple of examples that got me thinking about this. First, Criss Angel once clearly used a woman without legs in a magic trick in which he appeared to have a woman pulled apart. Second is the infamous Craigslist post where a guy wanted a legless man to dress up as a legless C3PO for a Chewbacca costume. Many people apparently got really offended about each of these. Is this indeed wrong, or not? And how likely are people to find amputees or people born without certain limbs who'd agree to this? And would those disabled people enjoy what they do, or just do it for the money?