#5: People Will Fill the Silence
Unlike the previous example, in this case I can personally testify to the proven effectiveness of our tip. In general, I have to say that silence is such a good tool that most of us humans are not good enough at using (and as explained here this is precisely why it works so well).

Once you’ve asked, the ball is very clearly in the other person’s court. So even if they are initially hesitant, at some point they will give up. It might be in gradual tidbits or it might be in a sudden spill but one way or another the information will eventually come forth.
