gistfile1.rb

module ArticleAccess
  extend ActiveSupport::Concern

  included do

    protect do |user, article|
      ## Guests
      scope { where("publish_at < '#{Time.now}'") }
      can :view

      unless user.nil?

        ## Redactor        
        if user.has_role?(:redactor)
          allowed_fields = %w(title subtitle)
          scope { all }

          can    :create, allowed_fields
          can    :update, allowed_fields
          cannot :destroy
        end

      end
    end

  end
end

removed comment

Ha. I was wrong. It was not the same. Yes, your code is totally ok.