As I have previously mentioned, I often travel to and from Hong Kong where my Thai wife and I have permanent residency (no local language skills etc as required here).
I mainly go for a change of scene and weather, but also for the excellent (almost free) medical care.
Every appointment slip or registration clearly states that these services are primarily provided for HK residents and that other foreign walk ins may be treated in an emergency, BUT AT THE FULL COST of the procedure plus medicines.
This is NOT "robbing" the foreigners, and is clearly stated, so no misunderstandings.
Last year I was in the waiting room for a regular check up when a nonresident man (foreigner tourist?) started getting agitated and rowdy about the time it was taking to be seen.
The staff tried their best to appease him, but with no success after 10 minutes, 2 armed policemen (not security guards) arrived and hauled him away.
They don't mess around there!