I feel like you might be appealing to consequences here a bit. Whether or not it is tractable in theory to follow the rule as an absolute (that is, to the letter) is a different problem from whether or not people will actually choose to do so.
It seems that Scott is more concerned about finding a formulation that can be followed to the letter in theory, while at the same time he has already conceded that most people will not choose to do so regardless of the formulation (and will thus follow the spirit instead).
I feel like you might be appealing to consequences here a bit. Whether or not it is tractable in theory to follow the rule as an absolute (that is, to the letter) is a different problem from whether or not people will actually choose to do so.
It seems that Scott is more concerned about finding a formulation that can be followed to the letter in theory, while at the same time he has already conceded that most people will not choose to do so regardless of the formulation (and will thus follow the spirit instead).