By Adam Taylor, The Washington Post
"Roof knocking" is a controversial Israeli military practice used in the Gaza Strip. It works on a simple logic designed to minimize civilian casualties. Occupants of a building are given a warning a few minutes before a military strike.
The first warning is generally a phone call. The second is a rocket.
The Israeli military has argued that the practice saves lives by giving occupants a chance to escape, but critics say the tactic creates confusion and can amount to psychological warfare. This week, the United States announced that it had used the tactic in Iraq.
Then don't knock just blow up all of the buildings. If there are terrorists in the building the other occupants already know it and are usually harboring them anyway. Someone is going to cry no matter what you do but majority rules and most Americans would say we need to kill all of the terrorists. If you're innocent get out of the way because you know who they are!