I would venture a guess that the person with the glock tucked in their waistband was either an idiot, or more likely, carrying illegally. I live in an open carry state and unless you have a concealed carry permit you can carry your gun on you at all times in most places so long as it's in plain view. Tucked into the waistband would require a permit and anyone that's been through the concealed carry classes should be smarter than to just tuck a gun in their waistband.