The Devil's Advocate protocol has been developed to assist making veracity assessments when someone discusses their opinion. The present experiment focused on protester actions rather than controversial issues and also included an adapted version of the Verifiability Approach. Participants told the truth or lied about protester actions and the participants' answers to the eliciting opinion and Devil's Advocate questions were compared. The Devil's Advocate approach predicts the difference in answers (residue scores) to be more pronounced in truth tellers than in lie tellers in terms of quantity of the answers (number of words, details and arguments) and quality of the answers (plausibility, immediacy and clarity). The hypothesis was supported but only in terms of quality: Truth tellers' answers sounded more plausible and immediate and somewhat clearer than lie tellers' answers. Truth tellers also reported more digital verifiable sources than lie tellers.