Speaking from personal experience, you are exactly right.
I used the service a while back just to test it out. I ended up at at place that was technically perfectly fine, but there were a few things that made me cancel and book another place - for a pretty hefty fee.
Again - technically there wasn't anything wrong with it. I haven't submitted a review because I don't know how to do it without being indiscreet.
I'd argue the opposite; I've found it to be very positive to travel and host with AirBnB and CouchSurfing when it comes to, ahem, the opposite sex. Friend-of-a-friend might get awkward, but then again, that's never stopped us either.
I used the service a while back just to test it out. I ended up at at place that was technically perfectly fine, but there were a few things that made me cancel and book another place - for a pretty hefty fee.
Again - technically there wasn't anything wrong with it. I haven't submitted a review because I don't know how to do it without being indiscreet.
Friends of friends is a great solution to this.