(1) I think using the word "technique" rather than "cheat code" or "trick" is an excellent idea.

(2) You say that Allen suggests using the common human reaction to sunk costs (which is to count them as if they were relevant to the decision). Now, as far as I know, it may well be advisable to use error to combat error. However, let's not forget that considering sunk costs in the case of exercise might make it harder to ignore them when it counts.