I'm astonished that Yelp would do something like this to jeopardize, and potentially destroy, their reputation. But there are far too many people telling the same story here for me not to believe there's something true in it... they can't all be liars and trolls. It makes me sad. I was a fan.
Would be interesting to actually hear a recording of the advertising sales pitch being made. Should be easy enough to set up and it's just a Youtube away from sharing with the world.