A method and system for preventing or obstructing a person from negotiating a transaction with another person, group, or entity in a population, includes verifying and crosschecking the identity of the person and the status of the national identification card carried by the person, as a prerequisite to negotiating or entering into a transaction, such as purchasing an airline ticket. The identity of the person is verified and crosschecked by using a biometric characteristic unique to that person. If an irregularity is found during the verification or crosscheck, or if the identification card is found to be invalid or expired, the person is prevented or obstructed from negotiating that or any subsequent transaction with any other person, group or entity in the population.