I hear this question all the time. Nearly everyone "knows" someone who is getting Social Security Disability in Knoxville or elsewhere in East Tennessee, but doesn't (in their opinon) deserve it.
Frequently, Joe and I challenge these people to name the freeloader. "Just tell us who doesn't deserve it and we'll help you turn them in." Rarely do we get any takers. Maybe it's all hyperbole.
In any event, I think those few who receive benefits but do not deserve them make it harder for those who do deserve them to get them. Joe and I (and probably most Social Security Attorneys) avoid taking clients who don't have a legitimate claim that they are disabled.
If you know someone who is trying to cheat the system, report them. The SSA has set up a fraud reporting site which is easy enough to use.