It was just such displays that forced the state of Ohio to enact a concealed carry law. Ten years ago, the ONLY legal mode of carry in Ohio was open carry -- and that was only because the Ohio Supreme Court read the Ohio Constitution and slapped down some prosecutors who tried to convict people for carrying handguns.
The Ohio citizens action group (I've forgotten the exact name -- sorry) organized a series of "carry-ins" and the result was that legislators finally recognized if they didn't want to see people carrying guns, they had to pass a law allowing people to conceal them.
Personally, I think if more fence-sitters (or those who don't even know there's a fence to be sat upon) saw more respectable citizens open carrying, it would rapidly lose its stigma. People in Arizona, for example, don't get their knickers in a twist when they see someone wearing a gun.