It's not just the cell phone zone.
LAX has a "quiet area" and there are often noisy groups of people there.
In all of the cases I see this kind of behavior in, there is enough availability in the rest of the AC. These are probably the same people that don't want their cigaretter smoke in their car, so they hold it out the window toward your car. This is especially bad if they are in an big SUV and you are in a Miata with the top down, because they don't give a damn where the ashes go.