Carrying and enjoying our Constitutional rights still requires some common sense. While OP meant no harm, masks and firearms in public are not a good combination.
Imagine what happens next time when an over-zealous concealed pistol carrier walks around the corner to see a masked man carrying a rifle. He draws and now all of a sudden you're staring down the barrel of a gun with a very jittery person on the other end, or there's bullets coming your waysince the over-zealous newbie decided he would be a hero and prevent a mass shooting.