I'm writing a post that's considerably longer than I thought it would be, so in the meantime, I thought I'd re-visit the question of whether I wrote a post about Zorro vs. the Grey Mouser. Certainly, I've never written a post that focused exclusively on them, or one that was literally about the two fighting each other. But I did write some optional thief rules that mentioned Zorro and the Grey Mouser as examples, contrasting them.
And the important thing to me, which maybe I should separate from that post for further discussion, is that the Mouser is Chaotic or neutral at best, just as you'd expect from a thief, but I consider Zorro to be Lawful. In a five- or nine-alignment system, the Mouser is CG, Zorro is LG or NG leaning towards Law. That's definitely not the way others see it...
How could I say such a thing? As hinted at in the thief post, I do not see Law as being about the legal system. It's about a strong sense of the way things ought to be, distinct from individual desires. Cosmic order + strong moral system. If the legal system of a community is, itself, Lawful or neutral, a Lawful character will uphold it. If it becomes corrupted (Chaotic,) then the Lawful character will oppose it. And if the Lawful character doesn't have a legal or military means to challenge that corruption, the next option is banditry or guerrilla warfare.
Zorro flouts the government because the government isn't Lawful. In fact, it goes beyond that; the man who would become Zorro is traveling with the replacement governor, who has heard of the corruption and plans to reform the government. He is assassinated, since the corrupt people in power fear exactly that. Zorro pretends to be the new governor -- thus, in theory, having legal authority to make the changes -- but takes up the (second) secret identity of Zorro to challenge the corrupt in what he believes the best way possible: he pulls a Robin Hood, stealing from the rich to give to the poor, rescuing the falsely accused, and basically causing trouble, in hopes of inspiring the people to revolt.
Part of the reason he doesn't just kill the corrupt leaders is because his dying cousin, the replacement governor, made him swear an oath not to kill anyone. In my favorite movie version, Zorro has a confidant: a priest. It is when the priest is killed by the main villain during a revolt that Zorro decides to reveal his identity and break his vow. So, it takes a *lot* to make Zorro go against the moral code.
The Mouser, of course, is a basically decent guy, but pretty self-interested. He takes up a life of crime because he wants to eat well. He doesn't take it up regularly because he's not a member of the Thieves' Guild. Mostly, he just rents himself out for various jobs, some of which are sketchy. He's definitely not playing according to some external rules of morality.