Thanks for the detailed response! The not-L answer makes a LOT more sense to me now (even if I don't yet find keeping it LN any worse than moving it to the others as described in the books).
Well, if I'm not yet convincing, consider a person with the opposite description than what I provided.
1) He places law and tradition above his own dictates.
2) He places himself under higher authority and believes he is subject to duties and obligations.
3) He believes he is subject to judgment by other and can be rightly and justly punished by them.
4) He believes that the law is objective and not subject to interpretation.
5) He believes his code should be assimilated by others and eventually become universal, so that there would cease to be disunity and conflict.
6) He believes that there exists a universal law which is correct for everyone.
7) He judges people on the basis of how well they follow the code he follows. In fact, his code may even specifically state which precepts/duties are required of believers and which ones everyone should be judged by.
8) The highest sin possible in his code is 'betrayal of other', probably with a hierarchy specifying which betrayal is worst based on his hierarchy of duties with betrayal of liege being the absolute worst.
A person who acted in this way would almost certainly be LN. I can probably invent a character that believes that but isn't LN, but off the top of my head, only by making his beliefs actually delusional.
I'm pretty sure I could come up with 100+ you would find non-chaotic by the 1e/2e/3e descriptions and not 'true neutral' in the 1e sense.
Oh, I'm sure you could. That's not the point. The point that I'm trying to get across is that 'adheres to a code' is too vague to really tell us anything. The code could be The Ferengi Laws of Acquisition (which are heavily chaotic and evil, but could conceivably have a lawful adherent... who'd probably always be confused and unhappy), the 4chan laws of the Internet, Discordianism as revealed by the Principia Discordia (which includes in its code, "There are no rules anywhere", "Everything is true", and "Even false things are true"), or something like your 118 rules that are just pulled out of someone's arse. Every belief system believes in something, and if you start listing what it believes it will start looking like something that could be called a code. But as bad as this is, believes in a personal code tells us even less except that it also tells us that they believe the individual is more important than the group and that the individual does have the right to just make it all up, which strongly hints at chaotic.
Even if I did, I'm guessing there are a lot easier cases to show that the standard 9-alignments fit some types of people really badly.
In full confession, in real life I don't believe that chaos or law are fully consistent and fully applicable labels for talking about real personal beliefs and certainly not as real, consistent and important as good and evil. So, if they don't fully fit real people well or for particular actions it becomes impossible to say if one is lawful or chaotic, then I'm not discomforted. I'm just trying to create what I think is as rigorous and internally consistent description as is possible for the concepts. I have some pretty good idea where this position can lead to paradoxes though.
I'm equally aware that some people don't believe good and evil are real either though, which throws everything in to doubt. I could be wrong. They could be wrong. We both could be wrong.
I should also point out that these positions are in game also alignment positions and a this argument that Law and Chaos are constructs and not really real is made intellectually by certain philosophers in my game world. And, within my game world their are of course people who believe for reasons that seem good and sufficient to them that those arguments are wrong. For example, I know how the Lawful Neutrals would answer the claim that accepting the above definitions of Law and Chaos leads to paradoxes.
In fact, among a certain strain of True Neutrals of a more intellectual bent in my game world, it is popular to argue that neither law, nor chaos, nor good, nor evil really exist, and among the evidence presented for this is that they don't really sufficiently describe any real people (in my game world), and that neither good, nor evil, nor law, nor chaos can be well and sufficiently defined.
So the problem we have is that claiming "The Alignments don't work for real people." is itself an alignment position that arguably just reveals the alignment biases of the speaker. A person within my game world would shrug and say, "Well, you adhere to the True Neutral philosophy of <some famous thinker>, so of course you would say that. But, you philosophy fails to account for...blah blah blah."
In practice, I've never had a player present a character to me that didn't fit somewhere on the 9 space grid.