Update 2: Guest said Airbnb told her today that the abrupt cancellation was due to 1 bad review. She is now banned from using the platform. (Hearsay, yes, and I mention it here in case we hear the same story from others.)
My ousted guest said she paid to stay at a prior listing and then felt unsafe after she moved in. As a result, Airbnb said she could leave that listing and gave her a credit for a future stay. She used that credit to move into my listing. My listing for 18 nights was $100 less than her credit which means her credit was $600. When her 18-night stay in my listing was cancelled by Abb after 5 nights, they did not roll her credit over and said she wasn't getting any refund for unused nights.
My assumption is that the prior host disputed not getting paid $600 for the prior stay (perhaps among other reasons). The prior host also didn't house the guest for any nights. The guest paid that amount in dollars to Airbnb; it was converted to a credit at some point, and she is not getting a refund in dollars or in a credit for any of it even though she paid for 20 nights and stayed for 5.
If we assume that all of the above facts are true, then this is what I'd look out for as a host:
1. Assume that any guest could lie anytime about anything + that Abb will potentially take your side one day and the guest's side the next day. So, make sure there's physical evidence to backup your claim against the guest or your claim that you are innocent.
2. Do your own screening of guests and decline any guest who's responses (and reviews) are unacceptable. Airbnb does not screen people.
3. Consider having guests sign a written agreement when they enter your listing. The agreement could outline the expectations and rules. This is allowed by Airbnb.
I rent in a suburban area. Housing has gotten very tight the past 18 months and I'm faced with more tricks from potential tenants/guests than I've seen in 20+ years as a landlord and 9+ years as a host. I do all of the above. I'm open to other suggestions from y'all as the US housing market evolves. Thanks a bunch.