"Olive Oil" .... you mean mixed olive oil that is probably 50% actual olive oil mixed with cheap edible vegetable oil they could find.
There is a whole lot of controversy and debate as to what can be labelled 'olive oil' .... if you look at the food industry as a whole, it's very difficult to know exactly where your food comes from, what its made of and where it originated from or even if its made in your own country. In Canada the regulations are so easy to side step that if your food packaging costs more than the actual food it is sealing, then technically, you can say the whole product is from Canada, even if the cheap food inside was produced outside the country and you don't have to mention where the food comes from.
There are industry approved labels that try to authenticate where olive oil comes from. Yes I know it is the companies regulating themselves but their incentive is to try to sell an authentic food product and trace and track where a bottle of olive oil comes from. A bit like how they sell and market wine.
Only problem is that once you can find an authentic bottle of olive oil ... it's $25 for a litre of olive oil from Morocco or Tunisia! ... and higher prices if you want something that is actually bottled and comes from one producer or farm in Spain or Italy.