How does it get to the US?
Commercially I have no idea, but all it takes is one clueless bachur who picks up a couple of bottles to bring home to his parents...
And honestly, supervision depends on the OBD. There were some this last shmita that sold sorry, distributed their products in regular stores like Osher Ad, while others only did it in special chaluka points, while still others distributed for free to kollelim and yeshivos
I have about 12-18 bottles sitting in my house. I did the biur personaly last year. If I knew less, I would send some to my parents for purim...