
Actually, the idea, like most good ideas, comes from Jules Verne, not
_The Gods Must Be Crazy._  In one of his lesser known books (I can't
remember which one right now), the protagonists are in a balloon gondola,
travelling over Africa on their way around the world in the balloon, when
one of them drops a fob watch.  They then speculate about the reaction
of the natives to finding such a thing, dropped straight down from heaven.
But the notion is not pursued further than that.