Newbie Questions - Black Dots?

[QuadMXRacer]

I have had Land Warrior for 9 months or so but only play very occasionally (once or twice a month). I have read on this board about black dots, what are they? It sounds like it helps people see you when inside of buildings? I always wondered how I could get shot when inside and not near a window.

What does it mean when it says "QuadMXRacer was killed" instead of saying who killed me? Normally it says "so and so killed QuadMXRacer" but sometimes it just says I was killed?

What does it mean when I get killed without ever hearing any shot? This only happens occasionally but sometimes I get killed with no shot, explosion, or anything?

How can you get killed repeatedly without being able to see anyone at all? Some maps I can't hardly take 10 steps after respawning without getting shot again. When I look around the hills I can't see anyone anywhere. Of course I assumed it was a sniper far away but I swear sometimes there is no one in site.

How can you shoot someone repeatedly without them dying? Sometimes a guys is running right at me and I am unloading on him but he keeps on coming and shoots me.

How can someone only get killed 1 or 2 times during a game when everyone else got killed 15-20 or more times?

How do people shoot you while they are running? With the gun bouncing around while running it seems awful hard to shoot someone else. I am sure it is a skill develped from lots of practice but sometimes I wonder.

With me being new to the game I can't tell if someone is cheating or if they are just very good. I like to give people the benefit of the doubt but my friends are convinced most of these people just cheat. I hardly join a game without someone accusing of cheating and it makes it me not want to play. Just wondering if someone could explain some of these questions so I dont get so frustrated. Thanks.