When my cousin was about 6, she was visiting a friend whose parents were having an afternoon party. She came home from her friend's house sooner than expected and told her parents that she was not feeling well. They took one look at her and knew she was telling the truth.
They ushered her off to bed.
When her dad bent over her to fix the covers, he smelled her breath. Yup... the kid was plastered. Apparently she and her little friend had been finishing what they found in abandoned glasses. <g>