I practically live in Airbnb around Europe for last 6 months and never had a bad experience, except once which was resolved + I was given $100 free credit.
OTOH I wouldn't be surprised to find that a lot of people DO have bad experiences, just because, well, a lot of people are just dumb. If AirBNB was wholesale editing reviews or revoking coupons you'd think that'd have attracted someone's attention by now.
Edit: It's also interesting because searching for AirBNB problems shows the opposite, where they side with guests that are bad, e.g.: http://www.airbnbhell.com/hosts-beware-mediation-say/ -- This is what I'd expect. Like Amazon, you can probably afford to piss off some suppliers if you maintain a stellar customer service reputation.
Really, what are hosts going to do? The hosts that aren't making a living off this will just leave or not, no big deal. The hosts that depend on AirBNB since they've gone and rented out properties specifically to do this (perhaps illegally) are just going to have to go out of their way to be nice about things since they don't have much recourse.
I also just signed up because I became furious reading the other reviews and realizing that I've also been duped by AirBnb and needed to vent to explain my situation.
If a host does not show or completely misrepresents the place --- goood luck, you are in for a treat with AirBnb non-service.
A place I stayed at had no kitchen (it was demolished and being renovated, this was not mentioned in the listing).
I could go on and on....
