Boys, where did you get the balloons?

At this time in my mother and pop's history they only had the older boys, Robin, Dee and Perry. They were on a long road trip but I don’t remember where they were going. At one of the re-fueling stops the boys went to the bathroom while pop fueled the vehicle. All three of the boys had a few quarters in their pocket, pop called this walking around money. Anyway, everyone loaded back into the vehicle and off they went. 

Traveling down the highway vehicles would pass mother and pop honking, waving and laughing as they went by. This happened several times before mother looked in the back seat. She noticed the boys all had balloons hanging out of the windows. She asked them where they had got the balloons. They boys said they bought them back at the last gas station. As far as mother was concerned the conversation was over. Pop on the other hand ask: “did you buy them in the men’s room?” Perry said “yes, there was a balloon dispenser in the bathroom!”