This natural consequence method worked really well with my kids as well. Rarely do they have to learn the same lesson twice. I started doing this religiously when they were constantly making me late in the morning before school and I realized there was no reason for me to get three people ready every morning and them to be getting no people ready in the morning. We had a talk about how it was going to go down. We set their alarms and listed their morning routine steps. I posted the time we were leaving the house. They were reminded that we were leaving at that time no matter what. In the morning, I took one child to school in pajamas and one without a lunch packed.
But do you think I ever had to remind them to be ready in the morning again?
Kids are way smarter than that.