Why This Doesn't Happen Anymore
The CIA solved the problem of human conscience a long time ago. They use two methods of wiping memory ala Jason Bourne...
A. Subject the agent's brain to a short burst of microwave radiation at a specific frequency. This prevents the brain from transferring a short term memory into long term memory. It interrupts the process. You essentially forget what just happened.
B. Use of the drug scopalamine. This hideous drug is a date rape drug on steroids. It renders you completely susceptible to suggestion for a 72 hour period of time. In other words you'll do whatever someone suggests to you and won't question it. When the drug wears off, the victim gets violently sick for 24 hours and has absolutely no memory of the last 72 hours.
This is our tax dollars at work, folks.