1) Metal zippers in sleeping bags conduct at high voltage, but not very well.
2) as was said, many experts considered doing all of the"right things" would probably have extremely little effect. Didn't they say like a ".1" out of 10? So anyway its kinda like cutting the handle off your tooth brush.
3) The presence of metal does not "attract nor concentrate" current or voltage. What happens is the electrical field around you induces a certain voltage in conductors depending on many things, that be as high as 300,000 volts per meter. So if you had a 3 meter long metal tent pole and held the ends in your hands, a million volts of potential would develop. Frankly the area of the coil wold be so large that the current through it just might be lethal, but the metal itself doesn't attract lightening. As the article implied "everything around you including your body" would have the same field applied to it. And you could be killed by a skin current "entering your orifices" (doesn't that sound icky :o") even without any metal around.
4) For me, I think the idea of moving a tent after a lightening storm starts is stupid, so its probably better to look for a decent spot in the first place, however for me at least - descent to the tree line represents safety.
5) unfortunately in the high country, often the ONLY spots level and soft enough to camp are directly under a tree, a large old tree isolated and standing nea a pond, but if its old, then obviously under it MIGHT be the safest spot.
6) as always, look around and think.
Jim