I was hiking in the Everglades two weeks ago and spotted a shiny object floating between two Cypress trees deep in the far reaches of the swamp. It was a Mylar balloon and the metallic exterior shimmered and reflected the rare sunbeam that broke through the dense forest canopy. It reminded me that no place is far enough away from the hand of humanity.
This is what happens to some of the balloons that get away from kids. My niece lost a balloon a few months ago and my sister told her not to cry - the balloon was floating away and grandma would get it. Presumably my sister thinks our mother lives in space since passing on 2 years ago. The situation repeated itself a few months later and Tara reminded Peyton once again that the balloon was headed up to Grandma. When Peyton lost another balloon recently Tara once again calmed the greasy-fingered kid and told her not to worry - and you know the rest. The apparently agitated three year old had had enough of this explanation and demanded to know what Grandma was doing with all of her balloons. I can only hope she's having a rockin' party.
I think parents feel the need to make up the balloon story for a few reasons. The first being that many balloons float back to earth where lucky little kids get to frolic with your kid's lost balloon. Explain that to a kid.
Another is that many balloons return to earth as litter - disrupting a wilderness slog through the swamp or falling into an ocean where a confused turtle will attempt to eat it - thinking it's a jellyfish. Telling your kid that Crush choked on their balloon is generally upsetting.
And finally - the idea that an 8-armed alien holding a bouquet of your kid's balloon on the moon is simply creepy and would freak them out.