unattached electrode lonely
The electrodes were not 'attached' to the patient's brain they were merely placed upon it. It is just about impossible to attach an electrode like that to the surface of the brain without damaging the very structure you are trying to record from.
BTW this means even if the govt forces you to have your head opened and electrodes placed on your brain you could frustrate it by thinking nefarious thoughts while flinging your head around violently (which will cause the unattached electrodes to move around). Or just pretend to sneeze will do it. Who would have thought possession of snuff would become a subversive act?
If you are worried about less invasive methods, there are reasons why they didn't do this years ago with an EEG net placed on the head. Think insulation, signal to noise ratio and lack of spacial resolution all combined. Not coming to a black helicopter near you soon.
Anyway, haven't all you paranoid people had your brain enveloped in tinfoil already? It's so much more convenient, and less ridicule inducing, than an old fashioned external foil beanie.