I can only repeat our experience in France. S-I-L arrived to help us move, helped load washing-machine, went grey - heart! Air ambulance, investigatory op., hospitalisation etc.. (He's absolutely fine b.t.w.) First thing he was asked when ambulance rushed him into hospital was 'Where is your insurance?' - before being admitted! He had taken it out, so no problem.
I suspect that his passport would have been impounded if he had had no insurance and not returned until treatment was paid for. They are not daft and do not mess about.