As financial firms have come under pressure from both sides in the gun debate, banks and credit-card companies are discussing how they could track gun purchases. Monitoring such purchases would be contentious.
— Read on www.wsj.com/articles/banks-card-companies-explore-ways-to-monitor-gun-purchases-1525080600

Good luck with that idea. You should stick to banking and not social engineering. This will drive transactions underground. Do these stupid banksters not have the ability to learn from history and basic economics? Demand will always be met.