Good luck with it under those circumstances. Being unwary is a facilitating action. When we were briefed, we knew it was going to happen and had to pretend ignorance. Thankfully our exercise was in a bar. Hard work for the trainees. BTW good looking women had better luck with the guys. Whoda figured that.
Noticed that in the NYT piece that describes Halper's assistant interactions with Papadopolous.
A little more difficult to train, but "turn it around." Ask questions of the inquisitor. Another fun technique is the white lie. Have a ficitonal history. While you owe the officials honest answers, no such duty attaches when dealing with strangers, Facebook, etc.