Sounds very US… I had to take some info on the topic here in europe and it appears that there’s a very much unalienable right for kids (and next of kin) to a fair distribution.

One can literally not change the part of the patrimony going to a child (without resorting to very complex arrangements that seemingly won’t be accepted by a judge should shit hits the fan).

Even though, for example, one learns he did not father a child -still cannot change the percentage. Tough luck for the other children, the wife…

Everyone has a right to be protected here. In the grand scheme of things it’s for the best.

And yeah, ethics is the basis for this simply you have to assume the position of the weakest one involved and not from the perspective of the one with the money ;-)