The system calling someone an exception may be describing its own narrow imagination.

Calling a person an edge case is often a statement about the design rather than about the person. Somebody who cannot use the form, the door, the timetable or the process is real and ordinary. What is narrow is the range of lives the system was built around. Exception is a word that quietly moves the fault.

When you hear that someone is an unusual case, ask how many people share that need. Then ask what it would take to include them by default instead of by special arrangement. Wider defaults tend to make things easier for everybody.