Well, I use knives a LOT, but there is a bug that makes it very frustrating. Sometimes, when you throw a knife at someone, it will dissappear when it hits them. Somewhat like a bullet would.

I get very angry when I hit someone with a knife, and it hits them, and just dissappears. [:(!]

~Phil

Yes, sometimes dropped weapons dissappear.

And sometimes you just can't see them (eg. they're behind a polygon)

And sometimes you can't pick them up (even if you can see them)

And if you can't see it, and you can't pick it up - it's pretty much not there! lol

Well, sometimes that happens to me, but then the knife usually reappears on the ground.