LOL! How in hell do you know that? A hundred could converge on one small town of 10,000 and kill everyone in the town or hold them hostage.
Hello?? Anything is possible with these fanatics. They could bring in 200 teams of 5 each, and literally cripple this country. Remember the havoc wrecked by the two idiots in the DC area sniper case? Multiple that 200 freaking times!
they would have to communicate and equip with those 1000 people to pull it off - the larger the circle, the harder it is to avoid detection and intercepts.