Speaking as a former security officer who wore a vest to work every day, I'm here to tell you that there is no such thing as a "cofortable" bullet-resistant vest, especially in warm or hot weather. I'm no longer in the security business, and would not even consider wearing a vest as part of my everyday attire. Just wondering what has you so frightened that you feel you have to wear a vest? And let's not forget that in addition to being extremely uncomfortable to wear for long periods of time, a concealable kevlar vest won't protect you from rifle roundss or head shots.
Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
Benjamin Franklin