Go buy your olive oil at Costco. They won’t sell fake olive oil.
LOL! I've got a know-it-all cousin who's an aggressive snob about almost anything you present to her. She also brags a lot about the bargains she finds at places like Costco. Recently she showed off another 3L of evoo, which is about as virgin as Cher and a hundred times more stale by the time my cousin pours the last of it into the frying pan. I tried to tell her that "gourmet" evoo from Costco, over $50 a bottle, is just blended bilge. But she's a world traveler (another thing she overpaid for) and I believe whatever I read on the internet. I don't have much use for cooking oil, but don't ever come between me and a dish of olives.
According to that guys refrigerator test the Costco brand IS fake.