I'd like to add this other suggestion to the list:

4) Switching to another target will cause you to lose claim of the previous target (unless they're spawned for a quest) to avoid people from "tagging" mobs for drops.

I've seen many people do ranged attacks on a target and then move to the next one, leaving everyone else to go kill the first one they tagged. From what I can determine drops go to the person who has claim, not the person who does the most damage or kills it. I've killed mobs that were pre-tagged whilst the player who taggged it moved straight to another target and never engaged the one he tagged and there was no drops from it. It had nothing to do with drop rate because whenever I claimed a target the drop rate was 90% for at least 1 item and when I didn't have claim 10 times in a row there was no drops at all.