A few weeks ago hornets started coming into our house here. They seemed to be attracted to the night light outside the front door, and when we'd open it they zoomed in. At first they were just a bit pesky, but more and more started arriving. I did a little research, and found out a few things: turns out hornets in the USA are (undocumented, I assume) European immigrants. Interestingly, the expression "mad as a hornet" seems to be American, I asked a number of Brits over here about it, and they'd never heard it. It may come from the daunting noise they make, but they're not very aggressive unless their nest is attacked, at which point they can be actually rather dangerous=when they sting, they deposit a chemical which attracts their mates to join in the attack; Carrie did get stung once, when she brushed one off her shoulder without looking....
They're actually fairly beneficial, but when their nest is near or in a house, are a problem. The nest we found was in our pigeon tower, right near the house, and on looking into it, I found a huge nest, about the size of a basketball. Since I once kept bees, I had a beekeeper's veil, and, having very very carefully covered myself up, sprayed the nest with a jet stream of hornet-killer. It worked, and the nest seems quite empty now. In any case, the swarm would have died over the winter, except for the queen (also dead, I now imagine) who snuggles down til the next spring.
So, here's the insect question: should I leave the (now drenched with hornet toxin) nest in place, or would it be an attraction for the next wandering hornet looking for a home? It'd be a bit tricky to knock it down, but I could do it.