So I just got off the phone with a rep from membership rewards. He made a one-time exception and awarded the 4x points for my recent booking through Tock, and suggested that in the future I should pay at the restaurant instead. I tried to explain how that's not possible, as only way to pay for a meal at these restaurants is by booking a pre-paid reservation through the Tock service. I'm still not sure he understood that point, but he did say that he was aware of others that had made the same inquiry and it sounded as though they may be open to changing this policy. For now it's frustrating that you can't use one of the main benefits of a card marketed specifically as having "foodie rewards" at many of the top restaurants across the country.