 Because they're the ones who aren't in 4chan chats making jokes about what they're going to do. They're not advertising in advance on social media trying to be heroes. They're not plotting. They're not asking questions that raise suspicion. They're out there quietly maneuvering to accomplish a goal. And they're the most dangerous ones because they're the hardest to track, hardest to find, and most likely to surprise. And that appears to be the case thus far with this would-be assassin of Donald Trump.