I'll post from the child's point of view here, since that's where I most relate.
I lived with my mom for 3 of the 4 years of college. This was made possible only because the day I graduated high school, she treated me like an adult. Now, it is important to know that I am the 7th child. I can't say it was this easy on her first or second when they came home from college. But, along the way, she learned a lot.
All through college, my mom did not wait up for me. That is not to say that she didn't hear me come in, as quiet as I tried to be. That is not to say that she maybe didn't sleep a little better once she heard me. But, she did go to bed at her normal bedtime once I graduated high school.
My kids being 7 years old now, I hope I have the courage to be the same, but, there's no way to know. I had an awesome role model though.