DnD defines LG as following traditions and a code, but they never said that it cannot be your own moral code. Chaotic has been variously described as Robin Hood (who actually do have his own moral code) or flightly as a fey (which RH is definitely not).
In other words, even the writers of the alignments don't know what they are talking about and contradict themselves many times on it. However, personally, I'd put RH (as portrayed in the stories and movies) as LG, and flightly as chaotic. I'd go so far as to say that most Good aligned people would be LG simply because doing good most of the time requires discipline, restraint and subscription to a code of conduct, personal or otherwise. Flighty (Chaotic) Good would be akin to Kiki (see sluggy.com), kind-hearted but "Ohhh! Shiny!"