I once created a server-side app that would monitor where certain search terms showed up in google rankings, so you could monitor change over time.

The biggest challenge we faced was that google dramatically changes your search results based on who you are, and where you are.

My point is - Justine Sacco isn't even on the first page of Justines for me. Maybe google just thinks Sacco is the best Justine for you, but it's probably not as bad as a "global uri".