Yes, mainly the transmission of diseases (some quite fatal & capable of wiping out all your herps!) as well as mites, which can spread some of the diseases, & also kill
"just" by the loss of blood they suck out (dehydration leads to organ failure quicker than many realize).
Most snakes are compatible in nearby (never the same) cages, but NOT all: king, milk & indigo snakes are some that many other snakes recognize as predators by
their scent instinctively, so you wouldn't house them in the same room as other snakes native from the same areas -I don't think BPs are going to notice them- they
aren't "neighbors", for example...but North American native snakes would be stressed...things like corn snakes & rosy boas would "know them as a danger".