As a practical example of this trade-off, imagine the cost of creating a documentary film. The environment might be hurt by driving all over, or flying a film crew around. But was it worth it? Depends on the film.
Let them make their "film" before you're a critic. :)
I don't see why a month of constant, needless flying is needed to for this premise. Documenting a bicycle trip using web 2.0 techniques, for example, would be a similar project without the subtext of needless consumption.
Also, the added effect to our planet by having a plane that's going to fly regardless carry 2 additional people (plus the weight of their luggage) is minuscule at worst.
I suggest a reading of "The World Without Us" by Alan Weisman for a look at just how durable our planet is. (http://www.amazon.com/World-Without-Us-Alan-Weisman/dp/03124...)
As for "The World Without Us", I'm confident that the world will continue to exist even if it's uninhabitable for humans. The issue is preserving conditions favorable to human survival, i.e. having a functioning ozone layer.
