Excellent. As additional explanation, these are the 3 values the Blizzard threat api returns. The loosely tanked ones will show up during tank switches, especially if something goes wrong or during taunt while one tank is building up aggro.
The (red) ones show up usually when adds arrive and initially target random people by proximity, heal aggro, etc. On boss fights I do not recall ever seeing it before a non tank pulls aggro and gets one-shotted. In toc vs the pvp bosses you will see a lot of it as well.