I'm sorry, but people make decisions like that automatically. You see someone doing something shady; you think they are suspicious. There isn't anything wrong with that. The fact that you may have a gun with you doesn't make it wrong either.
Now, if you decide to take the law into your own hands and use your gun against them because they were being suspicious, that is where it becomes wrong.
Now, if you decide to take the law into your own hands and use your gun against them because they were being suspicious, that is where it becomes wrong.