RE: Leaving a note
I can remember as a kid, there was ALWAYS a notepad either on the counter, or in the "junk drawer" in the corner of the kitchen. If _ANY_ of us went out "outside of normal routine" when no one was home to tell, you left a note. That included Mom and Dad. It could be as simple as "I'm next door watching TV". Prevented much worry of "why is XX late"

It was just the expected thing to do