Ah, a place to put my annoyances:
INPROPER COVERING
Ya know, when you are building an RT and your teammate says he'll cover you, then goes off to a corner.
To properly cover someone, you need to be RIGHT next to him, so that the skulk is running at both of you and you can hit him, rather than just at your partner, and sort of at you at an angle which is very hard to hit. In this case, usually the marine, on purpose or unintentionally, uses you as bait while you build.
What really comes to mind is south loop on ns_eclipse, where no skulk should EVER make it to the RT when you have someone covering you, because there is a good 50 FEET HALLWAY THE SKULK MUST PASS THROUGH. Nonetheless, my teammates always "cover me" on the far wall away from the RT and let the skulks run up and chew me down EVERY SINGLE TIME!
COVERING INSTEAD OF BUILDING/KNIFING A NODE
If you have 3 or 4 marines at a node. There is NEVER a good reason to cover, because if all 3/4 marines build at once, the RT will be done before a skulk has a chance to get halfway to your squad anyway. Seriously. And it doesn't take that long to stop building/knifing and pull your gun out anyway. In fact, the only time when I can see it proper to cover is when you are setting siege up outside of a hive.
