Yelp is pointing out to the restaurant that they're asking customers to violate the customers' TOS with Yelp. Nowhere is it insinuated that they themselves have

Yelp is pointing out to the restaurant that they're asking customers to violate the customers' TOS with Yelp. Nowhere is it insinuated that they themselves have an agreement with yelp. It is not being done behind the restaurant's back. The restaurant is paying the customers (in free pizza) to leave the feedback.