Again ... varies by state. No state allows you to "brandish" a firearm negligently, but some states are more strict than others regarding how strictly "concealed" is enforced. In Texas, people are paranoid about whether their gun can be seen. The term is "printing," and apparently in Texas even if the gun is completely covered, like with a tee shirt, if someone can discern from the shape that it's a gun you're still in trouble. Here in Connecticut, the permit is a pistol permit. Technically it allows concealed OR OPEN carry. The police would prefer that handguns be concealed, but if it "prints" or if the wind blows open your jacket for 15 nanoseconds so some twit can see that you're carrying a GUN ... no harm, no foul.
Again ... know the laws for where you are, and don't worry about someone else's laws.