It is neither. I don't tell my players what alignment to play. Well most of the time. I did once ask that everybody play some version of good because of the campaign I wanted to run. I let the players tell me what they want how they see their characters. I even allow evil alignments if they can show me that it will not become a major disruption to the party. Maybe I am not saying this right so that it is understandable but my issue is when a player says I am a heroic good type character puts down lawful good on the character sheet wants to get benefits that it brings like good aligned weapons and then proceeds to play in a way that a good character would not.
It's in your right to try to get characters who fit the campaign.
Man am I glad 4e got rid of "good-aligned weapons" though.
Arguments like I am just playing my character and their should be no consequences for my actions.
One reason I don't like alignment - the
kinds of consequences a player might suffer (especially if they do something non-drastic, like slipping from good to neutral). If you're going around burning orphanages, the problems are three-fold. IMO, they would be in this order:
1) You're being disruptive to the game. (Unless you've got a game where burning orphanages is a big part of it.) Expect consequences, like being dumped by the other PCs, being hounded by police/paladins/whoever, etc.
2) You're acting out of character. (Even most evil characters wouldn't do that.)
3) Oh yeah, you can't use your hold sword anymore, either.
The first point is so big I couldn't care less about point #3. The PC is being shown the door (becoming an NPC). He didn't just lost his holy sword, he lost his entire character.
An example how this works in game is this. I had a player who choose to play a lawfully good cleric of Heironeus. He was given a holy lawful good aligned sword that did extra damage to evil and chaotic.
The group had taken some prisoners from an enemy army. The cleric detected evil on them they were not. He offered to spare their lives if they gave information and did not try and to escape. They cooperated provide good intel. Did nothing to hinder the PCs in any way. After the mission was complete and it came time to release them the player playing the cleric announces he is going to slit their throats. To stop them from rejoining their army and giving any information to their leaders about the party.
I stopped play and asked him if he was sure he wanted to take this action because as the DM I felt this was a major break with his choice of alignment and how he had been playing his character up to now. He started to justify his actions as being the smart thing to do to protect the party because the other side didn't have any concrete information on them.
I simply asked him if he really thought that a lawful good character would give his word and swear on his holy symbol an oath to spare the prisoners and then turn around and kill them. That maybe killing them may have been tactically smart but was it honorable?
After a few minutes of thinking he agreed with me that it was not something that a lawful good character would do but he was going to do it anyway and he realized that he would have some major atonement to do and that while he was atoning he would be cut off from his god and his sword would not function as a holy sword.
The game moved on without bitter arguments of how dare you punish my character for his actions and led to some really good role playing as the cleric worked to remove the blood from his hands of the innocent men he had slayed.
I think you picked a very mature way of dealing with the problem. Since alignments are a very small part of my games, if they become important at all, nothing like that would likely happen in my games. (For instance, if this were Eberron, changing alignments wouldn't harm your cleric at all... but if a PC did that anyway, after the discussion, I'd just sit back and watch the rest of the PCs dump 'em. Possibly. It sounded like a single [but very severe] case of inconsistent behavior, but not actually disruptive.)
I think you have this impression because I use alignments in my game that I like to stifle role playing choices of my players and that I make them stick to what they wrote on their character sheet.
I don't, a player is free to take any action he wants he is free to change the way he plays his character. The thing is that their are always consequences both good and bad for the choices we make.
As I have said I expect my players to try and have some internal consistency in the way they choose to play their characters. This makes for a better game for everyone at the table not just for me as the DM but the other players as well.
I guess we just have different ways of dealing with that. Alignment isn't important to me, other than having something to rant about on forums. I'd rather deal with character consistency without involving the rules at all.