Yes this is idiotic behavior and potentially dangerous but... this stuff is everywhere and as has already been noted, a really poor attempt at making an "80" from "60". I have found the severity of corners associated with a certain advisory speed can vary enormously and therefore largely ignore them (as I assumed most did).
I do find it hard to fathom that man and machine would have had much difficulty taking a 60k corner at 80k.
Point taken though, one must have little to do to consider this fun.