Should I approach the Jehovah Witnesses loitering outside of my office?

[Minimalist]

Call the cops and report suspicious activity.  Maybe you'll get lucky and they'll shoot them.

I know you are joking, but no, someone holding crappy bullshit claims is not a reason to shoot them. But here is some dark humor about JWs.

http://www.ranting-gryphon.com/Audio/Audio.htm  Click on "Religion".

This is 'murrica.  People get shot for far less than that every day.