That was probably the reason the guy at ledgrow.eu used the mylar around his grow area to give it a "tube effect." Although some light may get wasted without the individual reflectors directing the light in a beam like fashion towards the plant, its true that the light would blend quite a bit more without the reflectors in the way, especially right up by the bulbs and not X inches away. I'm sure some light would be wasted since mylar isn't as perfectly reflective as a highly polished reflector, but I think his main concern was light blending. Since his grow area was more of a tube shape with mylar then most of that "wasted light" would be reflected back onto the plants eventually. It looked like the space between the lights and the canopy wasn't more than 24" or so. In an open area type grow, and without side-lighting, reflectors make the most sense. Keep in mind that these grows he's doing are supposedly only using 60w max. It looks like a 2' x 3' area or around there. 2w LEDs
This webpage starts at the bottom and reads up to the top,
http://www.ledgrow.eu/test7.html
He uses a few white lights to "complete the spectrum." Also uses IR light and talks about the importance of only using it during flower, and the benefits of side-lighting while using the same amount of electricity 62w. Anyway, he took his reflectors out for some reason when he started to use lights on the side. I'm pretty sure he did it because he wanted to move the lights closer to his plants since he had turned the wattage down, and keep the wavelengths blended enough.
If one was to use like 24 of the 4' single bulb fixtures(without reflector), and mount them in a Mylar tube like area, I think the curved Mylar would reflect the light enough.