From looking at their examples, they don't populate the 'ref' field of the ortb2 structure. There's an argument to be made here that the advertiser isn't being

From looking at their examples, they don't populate the 'ref' field of the ortb2 structure. There's an argument to be made here that the advertiser isn't being completely deceived because they're choosing to accept data without a 'ref' field which means they don't know or care - beyond keywords - what page the advert ends up on.