Good thoughts, but use common sense
[Lesson # 1 in how to spread AFB to you robbing hives.]
If the combs HAVE foulbrood.
I don't think its appropriate to say all robbing causes AFB.
It could, if the combs are infected, and it should be considered.
Throwing the combs away is a waste (unless infected).
I would inspect throughly for signs of AFB and proceed with caution.
I'd problably not offer combs from hives with ANY history of AFB.
Likewise, I'd not render wax from AFB hive either (the spores can be dormant).
Cautious, not paranoid.
There is always more than one way to skin a cat, that's of course if you're into eating cats.