TSA has had a downloadable for pax to fill out and carry for quite a while. It allows the pax to document his/her medical issues in detail.

Both from firsthand experience and reports, it works as well as you might expect. Most TSOs have never seen the form and it means nothing anyway, because 'anyone could print something like this up and say anything'. Other TSOs will simply refuse to even read it.

Bottom line, TSOs have the right to challenge any pax declaration of medical limitations and you comply or you don't fly. If you are physically incapable of complying, you are in for a rough time. I've had my inability to stand still and hold my arms high over my head challenged. I've had to 'demonstrate' how high I can lift my uncooperative arm, and on one occasion, the TSO tried to push on my elbow to make my arm go higher. I almost screamed, it hurt so bad.

Good thing I didn't, because if I had, I would have missed my flight for sure.

Sad thing is, this was allegedly caused by one of CLT's 'best' TSOs. Makes me shudder to think how their 'regular' TSOs are allowed to treat handicapped people.