I drove half way across my state yesterday to visit a gravity hill after finding it on Roadside America. If seeing this on the front page of HN less than 24 hours later isn't a sign, I don't know what is.
Maybe, but only if observed from the outside - collision of properties from within a sufficiently large sample.
From the point of view of the gp it is a collision of its own property (sample size 1) with properies of something else, of possibly huge sample size (all things discussed online) and not even independend (would gp have read the post and posted without having been there recently?).
Not exactly birthday paradox. This thing needs a different name.