There's organised crime, obviously, but it's not a big thing.
And if Australian started adulterating their olive oil to a level that was detectable, then a ton of media shaped bricks would descend on them.
I mean... Seriously, our media has nothing better to do than exposing fraud. Every other night, there's a section on something nutrition related. Just last week, they told us which fast food chains sold the healthiest chips. KFC for those who are interested.