I have seen many times here suggestions to cover the muzzle with tape or a balloon. Doesn't having something over the end of the muzzle affect the accuracy?

I will be hunting in Idaho, and my pack has a place to put the gun, so the hands remain free, but it does mean it will be carried muzzle up. I want to protect the load, but I also will need every bit of accuracy I can get.

Am I all worked up about nothing?