Last one out shuts the door

We implemented a new rule in our family last weekend, last one out, shuts the door. After the Schwan's employee picnic, Kelly and I were both pretty beat from the heat. But, we needed to get some groceries, so we took naps (Aidan and Mommy) and then headed to the store. Wendi opened the side door for Reed and Carter, since it no longer opens from the inside, and Kelly got Aidan. Wendi then proceeded to get the 'green' bags from the back of the van, and we went into the store. Shopping took a while, due to our exhaustion. About an hour or so later, when we leave the store, we notice a van with the side door - still wide open! Aparently neither Reed nor Carter knew to shut the door. We're just thankful that we live in such a safe community - Wendi's purse was there, untouched! So, last one out - shut the door.