I've got boas and ball pythons. I keep them in different rooms of the house and have separate feeding utensils for each group.
When I want to handle the snakes, I handle the balls first and then the boas.
When it's feeding day, I feed the balls first and then the boas.
I don't really believe that this is a very big deal unless you house them together, do not implement a long qt time, obtain your boas from an unreliable source, and/or have sloppy husbandry skills.
Just my two cents!!