Ideas like this are nothing new. As early as the 1960's, Jose Delgado unwittingly stumbled across a huge potential for mind control when he researched stimocievers. Originally they were intended to be small electrodes implanted into your brain that stimulated a certain area of the brain, which caused it to create more/less of a chemical, or make you feel a certain way, etc.
The intent was to use it as an alternative, hopefully more permanent treatment to disorders such as schzophrenia and bipolar. it was a huge sucess, but as the cliche goes, it worked all too well. They discovered that, with the proper knowledge of how to stimulate what areas of the brain, they could effectively control not only their movements, but their thoughts and perceptions to a profound degree.
I personally am not worried about mind-control becoming a dangerous possibility. After all, the possibility of the military suddenly taking over is a very real possibility. It would be quite easy for them to turn america into a facist military regime. Has this happened, or is it going to happen? No, and it doesn't look very likely. We have had potential for other effective methods of brainwashing, a human shock-collar placed on children would be extremely effective. DXM, a chemical found in robitussin and other cough medicines, can heighten the level of individual suggestibility in a child (and even many adults) so much that you could convince them of almost anything (even when taken in normal cough medicine doses, and even if they were aware that it had been given to them). All these would be wonderful methods of brainwashing and indirect mind control, yet we have not yet seen any of them come to fruition, and it's not likely that we will. As we develop technologies for mind control, we will doubtless develop technology that keeps it from being abused.
However, I have heard testimonies from individuals claiming to be controlled by stimocievers. At the Deoxy.org forums, a user who goes by the name 'theta' posted many threads and posts claiming that he was a victim of this. Many conspiracy theorist websites claim delgado was the antichrist in creating the perfect mind-control devices. I personally don't believe much of it, but some people prefer to be on the safe side, and try and stop any such research, just to make sure the worst won't happen (no matter how unlikely the past has shown the worst to be).