How do they figure out "maybe" so early?

I have so much blogging to catch up on, and one of these days I'll get started, but for now here's just a little tidbit.

A month ago, or maybe two, Owen was requesting something as we were driving somewhere. I can't even remember if this particular request was to do something special or eat some special treat or what, but I remember the ensuing dialogue:
Mommy (answering Owen's request): Maybe.
Owen (excitedly): Yippee! "Maybe" means yes!

I laughed a little out loud and a little to myself because I remember being a kid and thinking exactly the same thing about the "maybe" response.