You know maybe people wearing foil hats were on to something after all.
In all seriousness this is a great advance in neuroscience that would help understand many things about brain. On the other hand, potential for misuse is enormous. Can you even prove you had been interrogated if such a device is used on you?
I think it's going to be quite a long time before fMRI machines get to the point that you don't know one is being used on you. Room-temperature superconductors are probably a requirement.
In all seriousness this is a great advance in neuroscience that would help understand many things about brain. On the other hand, potential for misuse is enormous. Can you even prove you had been interrogated if such a device is used on you?