Why do insulation installers put insulation in upside down regularly?

I baffles me when I walk into someones basement and see the paper vapor barrier facing down. The vapor barrier, also known as kraft paper, is prevalent on most brands of insulation. This vapor barrier prevents water vapor from penetrating through and into the substrate material - such as your sub-floor.

The reason I am baffled is that if you are a professional insulation installer, you know the vapor barrier should face the living space. And if you don't know it, it is PRINTED RIGHT ON THE INSULATION!

I guess the boss does not tell his emplyees these things, unlike in the old days when people use to train their employees. New construction is where I see this most often, but of course, Harry Homeowner does the same thing sometimes. Next time you are in a basement, and you see insulation above you, and it is installed wrong so you can see the vapor barrier, read the instructions on the paper - it is plain as day. -Ray