Answer: Because they are being held captive and can't escape. :D
This morning my husband and I drove my youngest into the city to visit a sleep doctor. We are investigating whether his attention deficit problem and his speech developmental delays could be related to sleep apnea.
As I am pulling out of the driveway, I heard him quietly mumble something like, "...go out to eat?" When I asked him to repeat, he said, "What if I get hungry while we're out?" It was a perfectly pronounced, complete sentence and so cleverly asked, I burst out laughing. Then I answered, "Then I'll feed you."
So much for Daddy's surprise to stop at McD's on the way home. The kid had us figured out before we left the driveway.