Crackshot: My $.02 is that camo may be necessary for some things--ducks and Turkeys, that may have some sort of color vision, (but what about the years and years that guys wore their overalls and red checkered jackets, and STILL took lots of ducks?
Maybe the ducks are smarter nowadays?) but in most other instances, plain old khaki or Olive Drab clothing will blend well with the background. Even the red checked jacket will break up the human outline. But camo looks HIGH TECH and cool, no? (Dare I say "tactical"?)
Once I was photographing the Mojave Air Races from outside the fence, wearing a brown and black check shirt, and brown cords, and my kids got really upset that they couldn't find me, right in front of them , within 25 yards of the car.