Its not that they didn't start the fight, my thing is that they came for the kids on the first night. That's what I think is odd. The Timing Cause Ben tells Goodwin to get down there, listen, don't really get involved and to bring him lists in three days. But the children are taken that first night.

Unless Goodwin managed to somehow sneak back that same night(guess its possible cause Henry said the shore was only an hour away) and tell Henry that there were two children, and then Henry decided to just go ahead and send some people to take them.

By the way, in the opening scene, did you notice how Henry was looking up at the sky from almost the moment he came out of his house? Nobody else was at first, there had just been that noise, but Henry was looking up immediately, before the plane ever started to make real noise or show up overhead.