Happend with me too, booking and conformation were made without contacting me, without approval or even preapproval, just a late phone call from someone saying am coming , he had confirmation and paid money to AIRBNB while the place was not available,
The story of instant booking mentioned within the coversation above is unrealistic, even if it happened to be true, I did not know before hand about this instant booking , and I happened to decline two booking offers one week ealier to the (confirmed one) for unavailability , so how come this instant booking choice was switched on ?