In my experience, after leaving a peirco frame out for cleaning, I found a varroa mite on the frame. My bees did not have varroa. Seems like too much of a risk to get that many bees together - unless you can be sure that they are all yours - and free from mites. Of course, I have also lost hives to robbing, too - but not as a result of honey cleanup by bees. Bad management Don't intend to find out, either. Intending stay as far from creating an invitation as possible. Learning all the time! Tim Rich