. . .I'm not sure how pleased T'pau would be to know that there was no duel to the death after all, and that Bones tricked everyone into thinking Kirk died.
As T'Pau had already bent the rules by allowing Kirk to compete ("our laws are not binding on thee"), I don't think she would have had any room to complain when it turned out Kirk's death was faked. It was McCoy's trick anyway, Kirk didn't know he'd been given a mickey. The worst that might have happened was a diplomatic protest.