This is a commercial deal case, not a consumer refund dispute. United was making a major business decision about rent, site design and construction spend. Perth Airport was promoting a site by reference to future passenger movements and the expected relocation of Qantas terminals. Those forecasts made the site look more attractive.
The Court treated the statements as representations about future matters. That matters because a business making a future representation needs reasonable grounds. It is not enough to say the words were only an expectation if the commercial message tells the counterparty that an important future event is likely enough to rely on.
For small and scaling businesses, the lesson is practical on both sides of the deal. If you are selling or leasing an opportunity, keep your forecast assumptions current and qualify uncertainty clearly. If you are buying, investing or leasing, make the future assumptions explicit in the contract through warranties, conditions, disclosure schedules or pricing mechanisms.