When you hear people with novel and specific ideas… or conspiracy theories… or who listen to a lot of overnight call-in talk radio, say things like “It makes sense if you think about it”, that’s when you assume it’s safe to tune them out.  When they’re setting up targets and are about to pick up a firearm, then maybe you want to pay close attention to what they say, and maybe smile and nod a lot.  And maybe make sure they don’t have your address or phone number.