[Deprecated] DMZ 1.6.2 (DataMapper OverZealous Edition)

[eluser]BrianDHall[/eluser]
Say, what's a good way of dealing with validation where a field is only used on creating a new object - but is otherwise never used?

I want to use a password_confirm field to control account creation, but obviously beyond account creation it is never used. I'm probably just going to hack a custom validation rule that checks $this->id, or use a bit of controller logic - but is there a better way to handle this that is eluding me?