From another thread:
Just tell them they are breaking that law.
IC 35-47-4-3
Pointing firearm at another person
Sec. 3. (a) This section does not apply to a law enforcement officer who is acting within the scope of the law enforcement officer's official duties or to a person who is justified in using reasonable force against another person under:
(1) IC 35-41-3-2;
Just tell them they are breaking that law.