I'm a big Foursquare user because I travel alone a lot. Google Latitude trails in second place but I do use it. There is no doubt that Google Local is important to me as a customer and when I put my digital marketing hat on I see Google pushing a closely coupled social-local drive in 2013.
This Google Latitude prompt is new to me. The location is pretty new so it's hard to tell off a single instance whether this prompt is due to the venue or an upgraded Latitude.
They already use wi-fi signals to get a more accurate idea of a specific location. I'm left to wonder what these additional signals might be.
I do like to see Google talking about signals. Clearly 'location signals' in this context are slightly different from the quality signals we're interested in for SEO but it's the same mindset. After the most recent quality tester guideline leak we certainly know how important location is as a ranking consideration.