Even as an experiment it is terribly misguided and that something like this would make it into the production environment as an experiment is a clear sign that they are actually considering rolling something like this out to the GP.
I totally agree, I just think that "Google is currently experimenting removing URLs entirely from the search" would have been a more honest title.
It's probably that for that user that's what it looks like and then you combine that with HN's original title policy. It's not 100% perfect but it works most of the time.