The mark of an adult, in my opinion, is the ability to admit when one has made a mistake and accept the consequences.
I admire Ms. Richardson for accepting her punishment with grace and maturity. While I understand that she was grieving for her mother, what she did was wrong. Instead of taking a tantrum (unlike a certain former President) in public, she put on her big girl pants, and let the chips fall where they may.
It is a lesson we can all learn, regardless of how old or young we are.