I've pulled queen cells. I've checker boarded. I've added empty bars at the ends of the brood area nothing seemed to stop them. They kept on making queen cells.
once they start making real queen cells, they have already decided either to swarm, or replace the queen. pulling those queen cells will accomplish nothing. if you destroy them, you run the risk of finding your hive queenless.
better to remove the old queen and some bees to make the hive think it has swarmed. then either let them raise their own queen or order a new one. don't destroy the queen cells until you have you new queen in hand
if you are buying one. you never know what might happen in the shipping.