The first point is actually a large part of the reason I declined the help of a wheelchair when I need it. I've already had to deal with my share of ignorance with people telling me things like I'm 'faking it' or 'just being lazy'. It is incredibly frustrating and hurtful to try and have to justify yourself for something you didn't chose, and would much rather live without.
Although I can understand how there are those out there who genuinely do abuse the help that is given to disabled people, be careful and remain tactful. Because the majority of us are truly in need, even if it's for reasons one may not understand or are unaware of.
In my conversations with friends in chairs, dealing with ignorance comes up a lot. Have a read and make sure you're not one of the people we bitch about ;)