When in doubt about the veracity of a disabled person's claim to not be able to walk I would suggest the old weighted witch water test. Every terminal would have a 10' deep tank of cold water. The TSO would attach some standardized DHS weights to the wheelchair and dump the allegedly disabled person into the pool. If you manage to escape then you are clearly a terrorist and must be sent to Guantanamo to be tortured with extreme prejudice until you sign a confession. If you drown then you were telling the truth. You really were disabled and will not be required to be fully screened.