Anyone who's agresssive enough to send a starship just to attack a distant anomalous radio source dozens to hundreds of light-years away will be too busy fighting each other (nations or hives, makes no difference) to come here. Their efforts would all be focussed closer to home. I'd waste zero effort worrying about this.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort