If you carry around a weapon designed to kill as many people as possible in as short a time as possible, then I expect you are planning to use it. Why otherwise carry it around, except to be a dick about it.
And yeah, a dick with an assault rifle would also motivate me to leave the area.
Much like I'm not feeling much safer, because soldiers with FAMAS AR's are patrolling around Paris' crowded spots. The risk-reward equation for that only appears balanced at best. At least when it's a soldier, I know that he has trained on that rifle. With some civilian, who knows if they know how to operate their deadly toy, and whether they are prepared for someone else to stab them in the back, and grab their loaded gun.
An AR introduces unnecessary volatility into the environment. Also, if you feel the need to carry that, you probably aren't psychologically stable.