The end of every chapter has about a page with the heading of "Reversal," in which Greene discusses briefly when the law is counterproductive / does not apply. The chapter entitled "Do Not Commit to Anyone" has, in its reversal, "eventually you may find it worthwhile to commit to one side," with a brief explanation of how occasional commitment increases the value of coyness.

I do agree with you that the reversal section is more of a brief caveat than a full treatment of the weaknesses inherent in every strategy, but it is there (and by pointing out what a thing is not, one makes it clearer).