> Congratulations, you've just started building a database of everyone entering the country with biometric data that can be checked in the field with equipment

> Congratulations, you've just started building a database of everyone entering the country with biometric data that can be checked in the field with equipment costing less than $1000, and which can later be cross checked to find people traveling with false or multiple IDs ("this facial structure comes back as matching (person x) and (person y), and the gait is almost the same. Pick him up.") I assume you believe this can be done accurately, or you wouldn't be suggesting this scenario. In that case—what exactly do you see as the problem here?