I suspect that imms would be quicker to change your alignment, if you were in fact not acting good. Partly because they are more likely to watch for behavior based on this after reading it in your role, and partly because they know that what they are witnessing is representative of the character and not a temporary aberation or them misunderstanding an inference.

However, I don't think purely putting something like this in your role and never reflecting it in your behavior is going to get your alignment changed. You have to live in a manner consistent (which might not mean in line) with your role if you want it to affect you.

That said, when they see you acting this way, they are less likely to view you as a badly played paladin, and more as a well played non-paladin (or borderline paladin if such a thing exists).

That's my guess. Could be wrong, but you see the logic behind it so you can take it or leave it.