The Core

It's live

https://www.screencast.com/t/b8aCAEAiSo

This news came out on the same day. How...odd - http://www.bbc.co.uk/news/business-41397673

I haven't had time to dig into it, but here is the US, hotel searches show click-for-reservations links with associated reviews in the top spots and highlighted in yellow.

Google recently rolled out Hotel Ads (GHA) in the US. We've been running those. We bid against the OTAs (Expedia, Booking.com) and so you might see hotel ads from a hotel, from Booking.com or whatever, but what you're looking at is GHA.

I'm not sure if that's what you're seeing though. Normally, you would see the GHA results in the Local Pack

<added>
Clicking the price info icon turns up this:

Hotel prices
Hotel prices come from Google's partners who use a service called the Hotel Prices Application Programming Interface (API). Learn about the steps and ongoing tasks that partners take to send prices to Google.

Sometimes our partners offer special lower prices that aren't available to everyone. For example, a price might be available only to people who are signed in to their Google Account or on a mobile device. To find out if the prices listed aren't offered to everyone, select Information Information.

Yeah, when you click through for any one of those hotels, you'll get booking links that are GHA