That would be a legitimate concern if one lived in the city/urban environment when the shtf.
Out here, our "Gulch" is seventeen miles from the nearest tribal settlement, fifty from a small town, and our closest neighbor lives over a mile away... We are more worried about the damned black bears crashing our party than the two legged beasts!
My parents survived in rural MS after Katrina. You could hear gennies for a mile, minimum. There was little traffic as gas was hard to come by.
There’s also the smell of cooking food to contend with. That goes a distance too.
Moreover the sound of the generator could keep you from hearing someone/someones approach.