I came across this thread after reading an article on the new generation Honda Insight. If you look at this picture:
2010 Chrysler Daewoo Dodge Ferrari Ford Hyundai Acura Honda Photo Gallery it seems as though Honda has placed some value in getting some cooler air with a velocity into the intake. The path comes through the upper grill then is directed by the vents through the rad support cowl towards the intake horn (which is quite large & pronounced).
There are some conclusions that I can draw from this:
1) The designers/engineers feel that colder than engine bay air is beneficial. Otherwise they would have easily put the intake end on top of the rad or directly behind it (like they did in the linked AutoSpeed article) to get a warm air intake.
2) The designers/engineer feel that taking advantage of some of the velocity of the air that is coming through the upper grill to be beneficial. Otherwise they would have routed the horn off to the side between the drivers side headlamp and battery somewhere, and not gone through the trouble of designing the radiator cowl vents etc.
They have designed the upper grill on the new Insight to be fairly aero with the wide bars so they do seem to be taking advantage of the concept, but not entirely as it isn't 100% blocked...which it could be because its a 'mild hybrid' and that area isn't designated for inverter cooling like it is on the Prius.
2010 Chrysler Daewoo Dodge Ferrari Ford Hyundai Acura Honda Photo Gallery