I think that kids are more likely to see rules (including ownership) in black and white. A kid owns a crayon. It's hers. End of story.
Adults are more likely to complicate things with nuance and hypotheticals. It's her crayon, but does she need to use it right now? Does the boy have any crayons of his own? Did she agree to lend it to him for a certain amount of time? etc.
Smuffin would say that none of this matters if it's the girl's crayon in the first place. But what I'm saying is that these kind of things are more likely to occur to an adult -- regardless of whether they affect the end decision -- than to a little kid.
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another place and time, without a great divide, and we could be flying deadly high