Interesting. I guess the high-status behavior in the front is, "I need to pay close attention to pick apart this nonsense".
The high-status behavior in the back is, "I'm so important I will have better things to do very soon, so I want to be polite when I leave early".
The people in front want to interrupt and ask lots of questions. (It won't be nonsense, because the speakers will have been pre-vetted. If everyone decides the talk sucks, then they will just be quiet.)
The people in back will stick around for the whole talk, but might have brought something else to read or do. My postdoctoral advisor Kannan Soundararajan brought other work, and never visibly appeared to be paying attention to any of the talks, except when I talked to him afterwards and it was obvious he had understood much better than I had!
I also recommend Keith Johnstone's book Impro ("Impro" being the British word for what is called "improv" in the US), especially the section on status. You can learn to deliberately play low or high status, i.e. act like you're important or not, and see how people treat you differently. Really the same hack in a broader context.