Australia mostly follows the Brits with regards to floor numbering.
Some organisations follow the US standard, e.g. ANU: https://services.anu.edu.au/financial-management/assets/numbering-of-floors-and-rooms-in-new-buildings
But mostly we follow the Brits. Except for a heap of weird buildings on slopes, etc. where the ground floor is actually Floor 2 or something else...
Seriously? This is a painfully obvious prompt injection vulnerability (reminds me of SQL injection, actually). If you're offering a "summarise with AI" functionality, then you should be sanitising the inputs properly. It should be a simple call to the API to tell it to summarise a dataset or particular webpage -- not provide a query string.