Fails validation, but the_model.errors will be empty.

validations.rb

class TheModel < ActiveRecord::Base

  def before_validation_on_create
    #do some stuff
    setup_defaults
  end

  private
  def setup_defaults
    self.expense ||= true
    self.income ||= false
  end

end

obj = TheModel.new
obj.valid? #=> false
obj.errors.count #=> 0