I agree that one should be careful with gloves and hive tools. Neither of these rises to the exposure from moving comb from hive to hive.
Agreed, and one must know the source.
But you want to know what's really
risky? Taking hives of bees, sending them to a huge bee convention in California where they can trade diseases and pests, bringing them back, yanking out not just comb but comb full of brood covered with bees, sticking them in a box, adding a queen from yet another source, and calling this a "nuc." Can you imagine people spending money
to take such a chance at getting disease? Having just committed this folly, the question is what next?
Also keep in mind they're 3 weeks late.
What gives these poor creatures the best chance at survival? Drawing their own comb is safer from the disease standpoint, but the new queen won't have much to lay in until that's done. A couple of frames of drawn comb is a head start, and we're hoping the risk (for AFB minimal considering our source has never had it) is well offset by giving them a chance to be stronger before next winter.
But at least our gloves and hive tools are clean.