Who Left Grownup's Incharge. 

So I just finished reading "how to stop your grownup from taking bad decisions. " by Judy Balan and the book raised very important question. For the other questions check the book out. But this one just wouldn't leave my head. Was there a prophecy saying once you're 18 you're free to do whatever you want but before that you are chained to the feet of your parents throne ? And who says that once you're 18 you won't be blamed for your mistakes. But the most important, who said , that the mistakes made by parents should not be pointed out ? Will someone please tell me??? 

( ps if any of you brilliant readers have any idea, please leave an answer in the comments box. )