Double beds fit three?

When our 9-year old daughter was 4, we moved into a friend's house for a few months after we sold our house. We had a little double bed. We told her she couldn't sleep in our bed because it was too small. One morning, we woke up and were talking to each other. All of a sudden, from the bottom of the bed smashed against a wall, our little girl's sleepy head popped up from under a blanket and she said, "See! I told you there was enough room!"