Why does Bud think it's different to lie to a kid than to lie to an adult?

From the text:

I had to stop and think, it's one thing to lie to a grown-up, most times adults want to hear something that lets them take their attention off you and put it on something else. That makes it easy and not too bad to lie to them. You're really just giving them what they want.
It's different when you lie to another kid. Most times kids really do want to know what they're asking you.