Is it safe to say that if you are careful putting on the inner cover of a super that a few bees may be casualties?
The problem with bees is that they go where they want. Putting frames in a box carefully to avoid squishing the bees inevitably commit suicide by getting under the bar last second. There will be casualties no matter how careful you are. I don't use an inner cover. My boxes are very basic and I use a migratory cover.