Instead of trying to suppress from the wrong layer of the stick, just don't touch until published?

app/controllers/cards_controller.rb

@@ -21,10 +21,7 @@ class CardsController < ApplicationController
   end
 
   def update
-    suppressing_broadcasts_unless_published(@card) do
-      @card.update! card_params
-    end
-
+    @card.update! card_params
     redirect_to @card
   end
 
@@ -46,14 +43,6 @@ class CardsController < ApplicationController
       head :forbidden unless Current.user.can_administer_card?(@card)
     end
 
-    def suppressing_broadcasts_unless_published(card, &block)
-      if card.published?
-        yield
-      else
-        Board.suppressing_turbo_broadcasts(&block)
-      end
-    end
-
     def card_params
       params.expect(card: [ :status, :title, :description, :image, tag_ids: [] ])
     end