It would also very likely be impossible to prove. Unless you think the cops are going to believe some dude in a hoodie in summertime over a regular citizen. And even if they did, they still gotta prove it. Maybe his shirt just rode up a little and the gun became visible for a second, who's to say. While I have never showed a gun as a means to deter a dirtbag, I have on more than one occasion employed the tactic that Michael Corleone had Enzo the baker do in front of the Hospital where Vito was alone and defenseless. That is, stick my hand in my shirt in a very obvious way to imply I had my hand on a gun. It once stopped two hood rats heading for me and turned them around.