I'm not concerned about the lawful side of things, lawful in and of itself only vaguely applies as lawful evil ultimately means that laws are there to be broken if it serves your purposes.
Lawful neutral more or less means that you have a set of values that you live by, they may, or may not be in accordance with someone's laws elsewhere.
The pirate community, in the real world actually had a loose set of things that you did and didn't do in given situations. That are unwritten laws. So lawful (as long as not good) is an acceptable alignment.
Ultimately, chaos is concerned with balance between good and evil. Not in causing it or that it gives you permission to do anything because it, well chaos. In theory, a chaotic good character will do nothing evil because it's not good. Good and Evil are clearly black and white, so if you do something even hinting at evil... can't do it. Evil is slightly more flexable, but not much. Neutral... well, that's where psychopaths come from, or people who can't decide what to have for breakfast because it might upset the balance.
Or, that's the traditional meanings from the very, very old days.I like lawful neutral because it's flexible and lets you build a character who doesn't have to be bound by a set of laws, but has some code that they live by, but can act if something requires action.
True neutral... These are suppose to be the psychopaths and psychotics. In my games of the old days, true neutral was never an option unless you could give me a really good reason for it.