While a swarm of bees can be an intimidating thing; a dense living and buzzing mass of insects a swarm is not inherently dangerous. Swarming bees are not on the war path, nor are they likely to be aggressive, they are simply looking for a new home. Where that goes wrong is when the bees are made to be aggressive, or more accurately defensive, because they feel threatened by external forces. Which means that much of the art of bee swarm removal is conducting it in a controlled and knowledgeable way that minimizes the risk to both bees and passers by.