From the article:

"Then again we are in a technology-besotted age that rivals the twenties, when Marston popularized lie detection. And we live in a time when there is an understandable hunger for effective ways to expose evildoers, and when concerns about privacy have been nudged aside by our desire for security and certainty. “Brain scans indicate”: what a powerful phrase. One can easily imagine judges being impressed by these pixellated images, which appear so often in scientific journals and in the newspaper. Indeed, if fMRI lie detection is successfully marketed as a service that lawyers steer their clients to, then a refusal even to take such a test could one day be cause for suspicion."

And then there is the issue of "show me the money." For example, if fMRI can be shown to provide substantial cost savings over lengthy investigations and trials, and a lucrative industry can be developed around training and certifying a whole new group of paraprofessionals, then acceptance should become wider and easier.