Check out this article, called "Rio tourists to slum it in style" about a German developer who believes that building a high-end hotel in Vidigal favela is the next big thing for tourism in the Cidade Maravilhosa.
Depending on the day, my mood, my geographic location, the latest news, etc. I can understand - and likely argue in favor of - both side of this type of story.
Be it favela tourism in Rio, visits to Khayelitsha in Cape Town, homestays in empoverished but breathtaking Sapa in the hills of Vietnam, or any other such venture offering an "authentic" experience to those willing to pay, it is hard for me to decide whether I believe the end result is exploitation or a fascinating way to bridge social differences and recognize the value of otherwise marginalized people and communities.
For each altruistic, socially conscious visitor who is truly interested in understanding how others live, I imagine there will be 10 others who are keen on staying in a favela hotel for the Experience - just so they can take the requisite photos of "innocent schoolchildren walking home past another child, only slightly older, holding an AK-47 and keeping watch over a drug sales point" or "visibly destitute but smiling favela resident dancing samba with beer in hand and view of city lights in background" - and return home to impress friends and family with said photos and tales of authenticity and how, despite the occasional brush with gun-wielding drug traffickers (referred to in a very nonchalant manner), they were truly accepted into the Vidigal community during their 4-day visit.
As much as I am annoyed by the "Quest for Authenticity" in tourism (staying in a penthouse in Barra and eating sushi every day is just as *authentic* as playing cards on a stoop in Rocinha, although it's not necessarily *representative* of the way most brasileiros live...), is it really a bad thing? Is it harmful?
Again, back to the questions I can argue either side of, depending on the day.