Reading the financials shines a bit of light on this;
View attachment 212310
attached the balance sheet, highlighted liability called to account at balance date for 'unearned revenue' (what is also sometimes referred to as 'income received in advance').
attached the note highlighting the the amount of 'unearned revenue' made up of tickets purchased in advance.
This is as at 30 June last year, but gives you an approximate idea of what sort of numbers they would have had around Feb. View attachment 212311
So, if I'm reading this correctly, they had (last financial year) $1.7bn in cash and $1.2bn in unearned revenue ... so cash net of unearned revenue is only $500m?