Don's comment, while a bit inflammatory, is correct in the general sense. But you're dealing with a large opening, and an object far from the surface of the car. So it's not really valid in this context. What Kit posted is much more informative, because in general from a fluid dynamics stand point I'd be inclined to "wonder" (not make any real statements because that's complex geometry and fluid dynamics is tricky business) if they really did anything.
Kit, would it be possible for you to post where you found this information? I'd be really curious to read more about it.
In terms of the lack of hood pins and open ducts being dangerous? Well in theory that ducts would allow air to easily flow under the hood and out along the windshield, in theory, this could create some lift, because of the slightly shorter path. But I can't imagine it would be all that much, and certainly not enough to overpower the hood latch. In the example sighted above (the second not the first) I'd be more inclined to say he didn't quite latch the hood. As for "tearing" the latch from the lower support, there's no way these little openings are creating that much additional force, that sounds more like bad metal, or a piece of junk fastener.
But this is all speculation, I've only been an engineer for 3 years, and fluid dynamics in terms of flow over complex surfaces is not my forte. An Aeronautical Engineer might have better insights.
