Spotted this today in testing — Google is testing local reviews from Google+ Local as a snippet that was added on to the local location extension. I also spotted the status code showing in two of the three Adwords URLs. I tipped this to Barry last week and a few others weighed in.
This is very different than Google Shopping reviews that often show for larger companies — these reviews were from the companies’ Google+ Local page. It’s another small factor that could help boost click-through-rates for local businesses with a physical location and are earning enough reviews to generate the visible stars.
It seems like Google is continuing to test Adwords extensions across lots of different searches and changes appear to be coming. Feel free to submit any tests you see with local review extensions across different verticals here.