It would be incredibly foolish to walk into a business masked. I don't care if you're in Nome, Alaska. I'm going to react badly if I'm in there when someone does that. I hope that most other CCW holders would too. Not as in gun them down on the spot, but I might draw my weapon, almost certainly if it's more than one person. There are some things you just don't do, and that's one.
I consider those who cause innocent people to be defenseless through advocating and enacting "gun control measures" to be murderers by proxy.