@Jo802 There are many guests out there who have accounts from years ago but no reviews. If you are apprehensive about the guest, reach out to them and COMMUNICATE. Ask them why they are coming, can you recommend restaurants or places to visit -- a friendly email from a host can go a long way to getting information about the guest.
If you get zero response after emailing (and make sure that your email requires some response) then you can consider whether or not to continue with the booking. It is YOUR property, and the guest should suit you and it.