Final answer:
The subject of this question is Business because it involves a waitlist app and a store. The question is asking about the action to be taken if a party checks in on the app but fails to check in at the store.
Step-by-step explanation:
The subject of this question is Business because it is discussing a situation related to a waitlist app and a store. This implies a business context where customers are being managed. The question also mentions Yelp, which is a popular review and recommendation platform for businesses.