I have two porches and a deck. The front porch is a tiny little thing, horribly uncomfortable, the side porch is nothing more than a wood stoop with a roof over it. The deck is on the opposite side of the house. I won't sit on the front porch, it's just too small and too close to the road. I will occasionally sit on the side porch, if I just intend to run outside for a couple minutes when the kids are driving me nuts or when I want to have a cigarette. If I intend to be outside for a while, I will head out to the deck, unless it's getting dark, because the house blocks most of my view, and I don't like that.
On the flip side of that, I don't go on the deck if my kids are awake. There are three doors to the outside of the house from the main floor of my home; the front, the side, and the door that opens onto the deck. The kids absolutely cannot get out the front door. It's a double deadbolt, there was one key...it disappeared somewhere in the house. If the kids were to go out the side door, they would take off, end up in the road, get kidnapped, so on and so forth, but if they go out the door onto the deck, they will get distracted because that's where all their big outside toys are. I don't have to worry about one of them coming outside unnoticed if I am on the porch on the side.
In this case, I think they wanted to be seen, but on the other hand, I am starting to see how it could be normal. If the kids did get out the back door, they likely would have stayed on the deck or tried to come around to the front, where the neighbor or DB would have seen them, so I can undersatnd the reasoning. I just think there might be a little more to it on this particular evening.