To give some balance, the day these two brothers and their father died, there were continuous rocket attacks on Israel. At around 7pm, a rocket hit a high school in Ashkelon. A student from the school told the reporter, "We were playing soccer near the school and suddenly there were sirens, and we saw the Iron Dome rocket fire above us, and then we heard a large explosion and we realized it fell just near us. The police came and we directed them." The rocket fell on the rooftop of a nearby school building unexploded and was disarmed by the police. The IDF later released a statement saying it attacked over 50 tunnels and tens of hidden rocket launchers. The Hamas often places the rocket launchers near civilian homes for protection and this might have been the cause of the attack. The civilians, as perhaps the Hejazi family in this case too, have no real say and are sometimes forced to remain near the weapons against their will.
[1] http://www.worldpressphoto.org/content/swedish-photographer-...
[2] http://news.walla.co.il/?w=/2689/2587705 (live blog from the day of the attack, Hebrew)