I agree with mad_jock and Whopity. There is absolutely no need for this 'spy in the cab'.
Students should have been adequately trained and prepared for their solo navigation exercises, so should be allowed just to get on with them without over supervision.
"I lied to my instructors when I was a solo student, I see no reason why they wouldn't lie to me now."
Frankly I'm appalled at such an admission of unacceptable integrity.