Interesting thread. I'm a landlord with 30 properties and 1 Airbnb. From what I can see you should consider Airbnb a clearing house for your money that provides the absolute minimum in support and background checks. They will verify the pereson is who they say the are, check the ID and address and this is it.
Be leary of anybody who doesn't take their profile serisously. If they post a picture of themselves in a group so you don't know which one they are I think RED FLAG.
If they don't fill out their personal profile completely RED FLAG.
You as a host take the process seriously. If they want to rent from you they should also.
I don't use instant book because Airbnb doesn't care who they pass through to you. If they have a heartbeat and an address they are OK by Airbnb.
Instant book should not only require those basic characteristics but also a fully filled out profile and at least one booking with a 4 start or higher rating. (just my $0.02)
If they can't meet that characteristic then they shouldn't be allowed to instant book.
There are penalties when not using instant book, like your listing isn't shown first, but do you really want to rent to a person who doesn't fully research where they are staying. Do you really want the person who just intant books the first property that meets the price criteria?
I don't, I want somebody who cares as much as I do.
DO NOT trust Airbnb to filter guests for you. They are here to make money and that is their only purpose. You are who they make money off of, not the guest. That is the end of your relationship.
Set criteria and stick to them. I made an exception once for a small dog. The issues from that tenant are still lingering.
A vacant week is much better than dealing with the aftermath of a poor guest.