Seriously??? The cops didn't know if it was illegal? If they arrested the kids, they should know any and all ordinances and laws and rules for the country as well as the city! Grrr ....
My son was taught to NEVER EVER shoot in the direction of ANYTHING including houses, cars (even if a car MIGHT drive by) or humans. If he could see them, they were a possible target! Granted, people make mistakes with guns, but usually stupid people make those mistakes. These kids didn't even think of there being a possible target past their house. I live on 6 acres, my neighbor shoots his 22 rifle, in the direction of a field with nothing in the way for over a mile, and a 22 does not go that far. Plus, they shoot at targets on the ground at the back of his yard, and his yard is 1 acre. I would NEVER shoot towards anything in the direction of my barn or his house. Even across the open field, with nothing for a mile, you never shoot up and away. A judge in our area got shot in the neck in his garage from a bullet from a high powered rifle, shot from well over a mile away. He came outside, heard something in his garage. Turns out it was the first of what ended up to be 3 bullets that ended up in his garage. The shooter was shooting up at a hawk that was preying on his ducks. He was borrowing another man's gun. He had no idea the ramifications of those gunshots! Just coincidence he hit a judge. But, you can imagine the scare for the area and for the judge (and I used to work for him 25 years ago when he was an attorney) when he got shot!
Again, stupid people, not bad gun laws. Those cops need to know that guns are not legal to be shot toward another person's property. Period! Why would they even question that??? Geesh. Sound like you have wimpy cops. LOL