This is nothing new.  Part of acquiring a lot of state parcels in the past has been surveying the corners once the lot(s) are laid out.  Old school, not so easy as the monuments to tie into for control are nearly always not local.  Modern GPS surveying makes it a lot easier - differential correction applied to field coordinates (post processing) gets it done.  A lot of corners were set in the past with an even less accurate basis - inertial nav, this practice goes back a few decades.