Preferably with something smaller than a 2,000 lb bomb. And a flyers bearing a general warning to evacuate does not count when you won’t let them through your lines. It’s no different to the school bully holding their victim down and “warning” them they’re going to get hit.
And even if the Internet is back now, how did they warn anyone in the same 48 hours they bombed even more than before?
And no. They aren’t doing knocking. That’s something they do in limited operations. Not now.