You have an illegal kick foul in K's end zone = safety. The status of the illegal kick is what it was prior to the illegal act = fumble. Declining the penalty would give K a new series @ K's 22. IF it had been a blocked punt that had been illegally kicked, the ball's status would have remained a kick, giving R a choice of the safety or the ball at K's 22. IMHO, this would be a situation where you could ask R's captain to take a stroll over to within earshot of R's coach as game situation would certainly have a baring on the decision.