Interesting that not all in the one picture I could see had this. Also, do they do this all the time or was it just for this event? If just for this event, does that show pre-planning? If it was pre-planned, were they planning for a "just-in-case" or "head's up" this is what WILL happen?
It’s a smart move. But it would change like the lapel pins or “ color of the day “.
People eyes tend to see the gun first then maybe things around it. Anything to make a fellow good guy just to pause and think could be a good thing unless a bad guy does it too: