in reply to why a nodelet can be kept agains author wish?

Why should it not be allowed? Because it is not allowed in real life. How many times have you said "I wish I hadn't said that"? How many times has your wish been fulfilled? Besides which, what's a little negative XP going to do to you? In the grand scheme of things, not a whole lot. Just as in life, you roll the dice every time you say something. To alter the past is unethical.