radio that they re going to hit certain neighborhood. other times, they ve called homes and said to the people inside, get out, we re about to hit your place. other times they fly over and drop leaflets explaining where they re going to hit, which roads are clear for evacuation and when people need to move. some of those leaflets say things like israel is currently attacking and will continue to attack every area from which rockets are being launched at its territory. one other way they warn, the fourth way, is probably the most controversial. that s called roof knocking. they fire a low explosive charge or a missile with no charge to hit the roof of the building, to warn the people inside they re about to be hit as they will be in moments with a much more powerful missile that can level the whole structure. the israelis say they re saving lives by doing this. the palestinians say this is psychological warfare. that it s about keeping people off base, keeping them afraud. the israelis