The spa closes at 8pm. That's just a fact you can look up on the cruise app. So when someone checked into the "spa" on their location share at 10:30pm, their partner started doing some detective work.
Turns out there's a cocktail bar one deck above the spa with almost the exact same GPS coordinates if you're standing in the right corner. Three margaritas later the cover story fully collapsed. The kids were fine — they'd found the arcade. The adults were decidedly less fine.