EDWARD WEBB
Once again, people differ.  Let's say that the bomb planter is somebody who never felt that the police were watching him, he felt safe and suddenly he doesn't feel safe anymore, it has a great influence on him.  He might decide not to plant the bomb because somebody's watching him.  Psychologically it's very possible.  It's not just about the building, it was also that the bomb had to explode after the meeting so that the people would get the message.  If it exploded at 3 o'clock in the morning, there was no message, it was only a destroyed hall, it wouldn't mean anything.  If I was in a meeting and I am busy with terrorist acts and an hour or half an hour after I'd been there, there was a bomb, I'd ask myself "Maybe this was aimed against me."  It might change my ideas radically.