While I don't generally think of myself as a bad person, it makes me feel better about myself that something like this never crossed my mind before reading this article.
This is just so devious, and selfish.
While I understand that airlines can't question the validity of a request for wheelchair assistance, I agree with the suggestion posited in the article that at the very least, those requests which were made in advance should definitely be honored before the last-minute requests. It won't completely curb the actions of those who deliberately misuse the service, but at least it'll be less likely that someone who actually needs it will have to wait.