Not being a gun owner this may be out in left field. But if I had a gun and thought a person I was approaching or who was approaching me presented a danger to me you better believe my gun would be front in center letting them know very clearly the possible consequences of any aggressive moves on their part.
Heck I think even announcing “I am armed do not come near me.” would give the other person a pretty dang good idea that you were serious about defending yourself and that his best option would be to leave you alone.
In reality, going up to someone you consider “suspicious” and showing them that you have a weapon is likely considered “brandishing” which is a crime.