Not really, even in my worse app I never wrote anything in the face of a user... And you can't treat a user as a global mutable state if your code doesn't direc

Not really, even in my worse app I never wrote anything in the face of a user... And you can't treat a user as a global mutable state if your code doesn't directly mutate it. I obviously agree with the concept that he is a very good example for an external system on which you have no control.