After having 7 Supermutants (one Legendary) show up at Warwick Homestead...(4 settlers, no turrets emplaced) I was forced to call "Broken Arrow" and call in artillery. I got a screen prompt saying that friendly fire on settlements was not allowed. It occurred anyway. After the barrage I had dead mutants and two settlers killed. The remaining settlers were neutral to me but I could not longer use the workbench.

Anybody else tried this?

As far as I can tell, artillery in that settlement won't fire within it's boundaries, but if you have another settlement close enough by that it's within range of it's artillery, I've found that it will fire from there.

Also, I think you might mean 'Danger Close', Broken Arrow is the term used when a plane goes down with nukes aboard. Also, it's a good film.

Just out of sheer spite when the standing on the roof glitch occured at Sanctuary. Let's see, how fast I can get you down from there, or something like that. I called it in and when the first shell hit, they all started firing at me.

Just had a peculiar thought: What is to keep enemies from tossing artillery support smoke grenades into any of your settlements? After all, many/most of them should be smart enough to realize that where there is that kind of smoke, there WILL be artillery shells landing.