No worries. The good people with guns will take care of the bad people with guns.... and it's easy to tell them apart.... right?
[To be read in 1950's public-service film voice:]
That's right. It is very difficult.
But fortunately there are some subtle hints that can help.
These are hard for most people to notice.
But if you know what to look for, you might be able to spot these telltale signs if they are happening around you.
Is a person breaking into your house?
Is a person carjacking you?
Is a person trying to murder school kids?
Is a person trying to kill you?
Is a person shooting into a crowd at a parade or mall?
If so, that person might be a bad person.
Now, if you still aren't sure, you can consult with with someone nearby -- a family member, friend, or even a fellow citizen passing by. You might ask, for example, "Excuse me, but do you see that man over there beating that woman to death? It seems to me that the situation might be one of the telltale indications of a bad person. Do you think so, too, or am I reading too much into it?"
If you can't discern these situations at first, don't worry. After a bit of practice and some experience, you, too, will be able to navigate the difficult task of spotting the bad person.