It would help, yeah, but such a system would have to collect, verify, and cross-index biometric data very quickly and very accurately in huge volumes, and remain extremely secure. Those limitations seem pretty daunting to me, though I'm not an expert.

And if we did manage to create a system with that sort of capability, I'd fight it with guns, bombs, knives, fists, and teeth. Those who give up liberty for security etcetera etcetera.