Some will argue, that would have left otherwise but are prevented because of the circumstances, they have to get checked. There might be an argument there so cost has been borne. Who pays for the non-opportunity cost because they have to pay for a flight back anyway as part of organising there travelling unless they are staying in China
That come under travel insurance in my book.
How this works in my book the traveller pays everything and gets re-imbursed by the travel insurance operator.
If the travel insurance operator does not want to pay it or ought not to thing they should pay it, the government bans them as a travel insurance provider forever.
If travel insurance decides to wear it they can recoup through insurance premiums going forward.
That way the market allocates resources in the most efficient manner.
So the customer determines whether to run the risk or not, the travel insurance mob decides if operating in OZ or not and the traveller decides whether to pay higher risk of contagion through premiums when travelling to China or not and everything is reasonably allocated without charging taxpayers who have nothing to do with the activity!!!!
So taxpayers should not be asked to pay taxes to subsidises incompetent insurance providers let alone banks despite their efforts to sponsor politicians!!!
