I thought model.save is supposed to return false if there are errors in the validation. However, I just noticed that Mongoid 3 is returning true regardless of errors.

I have this validation in my model:
validates_uniqueness_of :_external_id, :scope => [:fanforce_id, :ff_action_id]

which is returning the following error when I try to add a new record with a duplicate _external_id:

but model.save is returning true.