Locked Out..

Today we came home from a very easy trip to Costco. Not sure if anyone has ever been able to say that. :)
I came in the house and brought Day inside. I usually come right in and hang up my car keys. Today was no different. I went back out to grab Lu and the groceries. Cole ran ahead to go inside. He yells back the door is locked. Yes, Day has locked us out. This has happened before. But she quickly unlocked the door last time. This time, she ran away from the door. Cole is sitting there yelling at her. He has to go to the bathroom!! She comes back to the door and she is laughing.
I am trying to talk to her calmly through the door. Cole chose the yelling approach, but in his defense he had to go! This goes on for a little while. I am explaining to Day why and how to open the door. Oh she knows how to open the door, alright!
It's been five minutes and I finally think to say, If you open the door I'll give you Ice Cream! And just like that the door is OPEN! WaaaLaaa!

Oops. I never followed through with the Ice Cream Promise.