Hosts need an option to prevent guests without reviews from instant booking. I understand new guests need time to develop a track record, but hosts spend a lot of time earning good reviews and aren't afforded the same feeling of safety when guests instant book without reviews.
This should be an option hosts either use or choose not to use. If the host chooses to use it, the guest with no reviews would simply need to inquire about the listing before being able to instant book it. I have submitted this to Airbnb as a product suggestion, but perhaps it would help them to justify developing it if other hosts post here that they agree.