I wonder what we should do about the problem when the spa is in a room and there isn't enough space to locate the receptacle required by 680.43(A)?

This is why we have 90.4
I see 3 choices
1. waive the 5' rule
2. waive the requirement for the receptacle
3. refuse it in plan review

Of course if they can get away with permitting this as a hydromassage bathtub the regular bathtub rules apply.
That certainly puts it back in the eye of the beholder. I suppose a "filter" would be the go/no-go point.