One day, they (developers pushed by middle managers) disable copy-paste on the login page, and the robot temporary stops working, until a couple of days later, when the robot found a way around it.
On to the next thing to do to stop the robot, but that previous "fix" is still there, with the thinking that "maybe that stops some of the robots", but it probably doesn't.
But there it sits, some ~10-ish lines of JS that will hang around until rewrite v6 when they'll begin from the beginning, and some months/years later come around to disabling it once again.
No, I'm absolutely not speaking from experience.