icepac, that is some weird stuff. the second vid with the tank, unless the animations are way off, his shots should have hit the trees. and it looked like he could see right through the trees. looking at the player's stats, he does more gv'ing than flying. it's possible he has a low end system that can't get decent frame rates and his system is glitching on certain objects.
i vaguely remember a couple of years back a graphics glitch where if you were in a tank with certain graphics settings, trees at some distance were invisible to you.