There is evidently no room in the NCAA rule book for institutional ethics.
But how would you quantify ethics or define ethics in a rulebook? Would the rulebook basically have to have an "I know it when I see it" type of description? I personally don't think that some sort of "action unbecoming" clause for players/coaches/admins/etc would be unreasonable. I remember having to agree to something like that in high school.
My gut reaction is that there should be a way for the NCAA to issue punishments in the PSU case (pending proof, naturally...this is the US after all), but I would hope that this case doesn't result in poorly-thought-out knee-jerk reactionary rules.