Yup, it is kind of prevented now (otherwise the Silk Road would've been shut down long ago). From the paper's conclusion: "Our results show that Tor’s location

Yup, it is kind of prevented now (otherwise the Silk Road would've been shut down long ago). From the paper's conclusion: "Our results show that Tor’s location-hidden servers are not really hidden—or rather they were not really hidden prior to the recent introduction of guard nodes as countermeasures to our attacks." More info: https://www.torproject.org/docs/hidden-services.html.en https://www.torproject.org/docs/hidden-services.html.en (where they reference the same paper)