Remember that beekeepers; let's assume that these are honey bees and not bumble bees, though they look very different from each other; only use smoke generators and protective clothing because they are invading the nest, the hive, to get honey or to check on progress, and that makes the bees rush to protect it. They don't get stung otherwise; if they leave the hive alone,they never will get stung. When was the last time you got stung by a passing bee of any kind?
It's a fear without foundation, even with a honey bee colony. But a bumble bee has no colony; its mates don't rush out to protect the other bees and the colony. It just lays an egg in a single place, alone, and the bee grows up as a solitary individual, a billy no mates!