I've enjoyed my four-year relationship with Airbnb and plan to continue (as a Super Host), but I have a few suggestions regarding vetting of guests:
You say you require a profile and picture of a potential guest, but you don't really. I get a lot of "Hi, I'm George" and that's it. Usually, these are the folks who just signed up a few days before. I also get a lot of "profile pictures" not of faces, but bodies from the shoulders down, or scenics, or pets, or anything but what the guest looks like. I usually decline people like this. I want to know that the person knocking on my door is the same one who made the reservation.
If a brand new member -- potential guest -- has not had an airbnb experience to warrent a review, I thought you at least required a reference. That was required of my as a host. I would like the same kind of reassurance.
Okay, that's my two cents. Bon Voyage ... Mike DiPrima/Atlanta, GA