It happens in the State where the patient is located. I could see my patients via a HIPPA compliant platform if they were in a state I was licensed in. Didn't matter where I was. I did see a few when on vacation in Mexico a few years ago. Defeated the purpose of a vacation but that is another story/my problem.
There isn't a mechanism that can prove where a person is. I would ask them to show me a view out the window, if I could see green grass or palm trees, (in January) I could conjecture they weren't in Minnesota.
Lower interest rates will help me buy eggs. My great grandchildren can pay it off.