Says you.
What about people who are mistakenly suspected to hold crucial info, and are tortured as a result? They either have to lie (thereby wasting our resources and facing brutal consequences) or attempt to last through it.
Moreover, think of what brain scans could do for death row criminals. Absolute, inerrant way to determine the guilt of a suspect. No more innocents dying.
At the very least, undergoing the scan should be a voluntary option for captive.