That does make sense, but unfortunately it will still cause problems.  Specifically, your example CZML won't validate against the schema, because the schema says that `reference` has to be an array.

So I think the schema needs to be as I said originally, but the generator needs modifications so it doesn't create the unnecessary writer.  This could all be avoided if you switch to a string instead of the object with the two properties, but if you don't like that idea I'll look into what it would take to fix the generator.