EJohnson wrote on Jan 15^th, 2008 at 4:04am:

Try moving your leg around when someone is attempting a CT Scan. Childish non-compliance, easily detected, and easily remedied. :P

Try thinking about something else during a CT scan.  See if the doctor claims you are being purposefully noncompliant.

There is no way of ever knowing what a test subject is thinking, so any test that requires them to think of a certain thing, or not to think of certain things, cannot possibly be a valid scientific test.

Failing everyone suspected of inappropriate thinking is the only recourse, and that is simply untenable.