I found "Gringo Trails" at the library. As a frequent traveler, I was interested in their take on the advantages and disadvantages of tourism. Most people travel to see (touch, taste, smell, hear) new places, to experience different cultures. But what if you were simultaneously destroying that place?
I took exception to their implicit logic early on: the movie had a text panel that said "as tourism has risen [in this South American location], the number of Anacondas has steadily declined." Wait, what? They don't actually say it, but the implication is clear: tourism is destroying the snakes. But the reality is a lot more nuanced than that: I don't doubt the Anaconda population is declining, nor do I question that tourism is increasing. But (and why do people utterly refuse to remember this?) correlation does not imply causation. Anacondas are probably dying off because of habitat destruction. Tourists are visiting to see the Anacondas in their natural habitat: tourists aren't the cause of habitat destruction, in fact they're pouring money into keeping the snake's habitat (nearly) pristine. It's slash-and-burn farmers who are destroying the snake's habitat. So, if anything, the tourists are helping the snakes. My logic is based on zero research (so you shouldn't put any faith in it), but I believe the filmmaker's was as well: show me science-based causation and I'll buy your premise.
Damn it people, CORRELATION DOES NOT IMPLY CAUSATION! Get it through your heads!
They certainly manage to show a number of places where tourism has had a destructive effect - I've been to some of these places, and I know they're right about that. The final play was to hold up Bhutan as a model: travel is regulated by the government, it's $250US a day, and you can only get in with a tour group. This has meant that they get old rich people who are there to actually see the place, not just to party. And limiting the number limits the effect on the environment and culture.
For the most part I agree with this, although it would have severely shortened my trip in southeast Asia. I was paying maybe $15US a day for a hotel room and food on that trip for six months: at $250US a day, I would have been there less than two weeks on the same budget. The movie as a whole was at best mildly interesting, and at that I think you'd have to be a fairly dedicated traveler to find it even that appealing.