le without gear. they become less capable of defending the hive from pests and may even weaken them to a point that they subcome to some new disease and pests.
my personal opinion
opinion without facts. i remember how sick bees were in old days. Brood area was full of holes because hole was sign of dead larva.
On another hand your clever idea means that beebreeders do not understand much about diseases.
Bee diseases have developed before a human walked on earth. Man has not made those 32 diseases and pest which are in beehives.