I up when I feel like it but I don't sit there and circulate as you are implying.
The clues are there and there are only a couple of maps where they can't get to hq without flashing something.
If I feel like defending, I do with great vigor and often get the attackers before they drop.
I don't concentrate on HQ.......but I do watch the entire map for signs of an impending attack............the entire map.
Try zooming out some time, it's amazing how you can see the future.
