Well if it uses MRI (although miniturised) should be pretty easy to detect/mess with strong magnetic fields around your head (a tin foil hat wouldn't do - but s

Well if it uses MRI (although miniturised) should be pretty easy to detect/mess with strong magnetic fields around your head (a tin foil hat wouldn't do - but something ferrous may !). Perhaps we should stop saying tin-foil hat and say "ferrous material hat" ;)