Is a wheel chair a "cast", "splint", "brace" or "protheses" that is "worn"?
The way I'm reading this is that those devices are subject to some umpire discretion. Wheel chairs are not, by the guidelines of rule 4-2 and R/S #55.
I'm not trying to be silly, but sometimes when a Federal mandate butts heads with common sense, you wind up with a big heaping pile of "silly"!