hedwards: What you're saying here applies to any and all systems that allow people to define their own characters. It also ignores the fact that the DM can just conjure a dragon to smite anybody that's ignoring their character too many times.
Not exactly true either. Vast majority of traits are fairly easy to define: You get strength, sure, how much you can lift, how strong you can punch, how far you can jump perhaps, simple right? Same applies to dexterity or stuff like that too, it's really easy to narrow down. Stuff like intelligence and charisma are a bit harder, but they're still pretty easy to nail down fairly accurately. Skills, like how well can you use which weapon etc...
However, how do you do that with aligment? What is good? What is evil? What is neutral? That's a debate I've had far too many times, and it ... Well it just doesn't work like that. I'm not saying all aligment systems necessarily need to be bad, but when I have to pick between 9 aligments that are either too restrictive to grasp an actual human psychiology or too loose to do anything, I'll rather opt for none at all. The only way I could see around that is that whoever 'creates' the character also provides a background and set of character traits, but I think that would lead to even more arguments. You can't have those about Strength, if you're not strong enough to lift that fucking huge rock, you just won't. But what happens when your good character decides to kill a family and use their blood to start a ritual which is the only way to stop an invasion. Strict DM would say your character can't, because he's good! Good doesn't do that, good looks for a way out! And... Uh... No, just no.