At that level the same happens here.
Even well off people arrive in the UK for treatment of expensive ailments or even child birth, take the free treatment and venture back home wherever that is and dodge the bills. They amount to ten of millions but in a budget of billions it is chicken feed.
in a country where treatment is free there are few if any measures in place to seek or take payment from anyone. The percentage of those who need to pay is so low that it’s not even economic to set up a “pay here” facility at all hospitals (as much as we would like to take the money off them)