Caution is advised when taking contradictions as a pointer to deception. This is because people do honestly forget factual accounts of a story and thus end up contradicting themselves. At times, people remember their own versions of a story, which may differ from others. This is common and has been seen a lot of times with witnesses in courtrooms giving different accounts of things that happened. Therefore, it is not always true that a respondent with contradictions is telling outright lies. Therefore, follow-up questions should be used.

Say a social engineer is targeting a particular person in a company using a thumb drive, for example, the procurement manager. The social engineer has to make sure that the thumb drive is inserted into the procurement manager's computer so that he can install malware that can perform some malicious operations, such as copying data. He will work out a pretext that fits the reason to see the procurement manager and proceed to try his luck. Having confirmed that the procurement manager is in, he might go to the reception only to be told that the target is not in. However, the social engineer had done due diligence and ensured that the target was in and this is a contradiction. He may follow up by saying that the meeting was preplanned the previous day but he has a bad memory and thus could also have come on the wrong date. This follow-up could be responded to in two ways; the receptionist may stress that the target is not in or may say she will go check whether he is in. The second response identifies more contradictions from the previous response. To save the receptionist's face, the social engineer may appreciate her willingness and say that he could also have confused the dates. That way, the receptionist feels at ease with the social engineer which is good for the attack. If the response was that the manager is not in, this lack of contradiction may mean that the target might not be in or might not be seeing visitors that day. The best way to handle this would be requesting the receptionist to confirm a day that the manager will be in. It is a win-win situation in both scenarios.