Hi @Lizzie Great to hear from you.
Would only count the "No Show" as someone who doesn't arrive at our listing and the button would only become active from 00.01hrs next day and then the guest would be unable to leave a review.
The guests profile would be highlighted with a "No Show" in the similar context as a Host whom cancels a booking
If someone arrives, enters the property and does not stay then this is a totally different experience and subject to a review by both parties.
Hosts take a lot of time, effort and expense to prepare their homes for guests. Many times I have waited up till midnight for a guest to arrive ( my check-in is 1600hrs - 2100hrs) and when they can not be bothered to arrive then the "No Show" button can be activated.