Agreed! A legal obligation to do a prenup would be like a law protecting you from the law... Perhaps you can scrap the laws about custody, alimony, etc. in the first place and let people figure it out by themselves.
Or you could just scrape the laws about custody, alimony, etc. and just let people figure it out for themselves. If the child is old enough (say >8 yo) ask them which parent they want to stay with.
