Wow paladin code of conduct forums are painful to read and pretty much describe the one of the major reason everyone i know avoids the class. Its less on the player side and almost always on the GM side (i GM more than i play). Lawful stupid came about because of GMs absurdly strict enforcement on paladin conduct so i handle it like this.
1) Your alignment is relative, im not tallying up every little time you ignore a law or commit little minor acts of evil.
2) I care more about your paladins deity/personal code of conduct than i do your actual alignment. Ultimate question is "is your deity pleased with you" usually i would go over this with a player before the game starts and establish an actual code of conduct. Lawful can be fullfilled by adhering to your deity/order's code even if it violates local laws. However swearing an oath is serious and requires atonement to break.
3) In order to actually fall it requires significant violations of your code of conduct. Grey areas especially are best ROLEPLAYED into how your paladin deals with them. This means if there is no right or wrong answer to a problem or both options arent really good, i will not penalize a player for playing the game. I love presenting morally difficult situations to characters in my game, but i wont ever strip a paladin who is trying to do the right thing.
4) Atonement is only requires for significant alignment violations
So in short, paladins at my table are largely safe from falling as long as they are trying to stick to their code of conduct and i even go out of my way to reward good roleplaying or "taking the higher path" as it goes. That sad, they dont need to do non lethal and vow never to kill, they are still warriors and have free reign to even be aggressive in their pursuits. Not just defensive. Pass judgement on defeated enemies/coup de grace if they judge them worthy of such a fate. They dont have to take prisoners ever. They can even go so far as to ignore chaotic actions of party members such as rogues and necromancers. Provided they arent working towards evil ends. When i play a paladin sometimes my paladin will "turn a blind eye" if it is something he doesnt agree with or simply accept that people are free to choose their own path. Anyway hope this puts some new perspective on an otherwise difficult class.