topics_removed_events.each do |ta|
      num_adds = topics_added_events.where(eventable_id: ta.eventable_id).count
      num_removes = topics_removed_events.where(eventable_id: ta.eventable_id).count
      if num_removes > num_adds && TopicPolicy.new(user, ta.eventable).show?
        topics_removed_to_include[ta.eventable_id] = ta