Yes, we have had this happen twice in the last few weeks, when we temporarily turned Instant Book OFF because we were offering a current guest the opportunity to extend their stay and wanted to ensure these dates weren't booked instantly in the interim. YES, we did save the changes, and went back in to confirm that Instant Book had been turned off.
The real issue is that when Instant Book has somehow been flicked back to ON by Airbnb, the additional requirements for Instant Book guests (which we ALWAYS have turned on when we have Instant Book turned on), are NOT turned on, meaning guests with NO prior stays or reviews have been able to Instant Book.
Have we attempted to get help from Airbnb to sort this out? Seriously? Help from Airbnb? We've truly given up on any form of assistance from Airbnb, even rectification of an issue their own system has somehow created. Someone has clearly been stuffing around changing the Instant Book system (the layout/ appearance has now changed), and they have caused issues for many hosts. We couldn't even be bothered any more to try and raise this issue with them. Great CS system as far as Airbnb is concerned, as it has reduced the number of calls for assistance/ notification of problems they are receiving - hosts are just giving up.
@Phoenix14 @Pete2785 @Sarah977