There is absolutely no reason a guest should be allowed to rate a listing based on cleanliness, accuracy, value, arrival, and location if they have never been to the location! Same for hosts: we should not be allowed to rate a guest based on cleanliness and observance of house rules if they never stayed in the house!
I have been in the situation a few times now where my guest cancels on the day of the reservation. I feel like I am forced to give a refund if it is requested (which, it always is), even though my cancellation policy would require them to pay the full amount, because they have an opportunity to review me. Who is going to give a positive review to the mean host who didn't give a full refund upon request?
Also, if hosts are marked with a "scarlet A" when we cancel on a guest, should it not be the same for a guest who cancels last-minute on us?
This is the logic your developers need to put into place: if a guest cancels on the day of his or her check in, reviews from host and guest are disabled and an automatic review is posted to the guest's profile, "Guest cancelled reservation on the day of check in."