Sure, it will be voluntary at first, and then eventually become the only way to board a plane/train/boat. At that point, someone will suppose that if our scans

Sure, it will be voluntary at first, and then eventually become the only way to board a plane/train/boat. At that point, someone will suppose that if our scans are good enough for the government to identify us for something so crucial, why can't we also use it for ID/driver's license/form of secure payment/house key/etc? After this has been established, yes, biometric identity theft will be an issue. We'll see a similar situation just like a US SSN - no one needs it but the IRS to collect taxes, yet everyone asks for it because it is the government's only way to uniquely identify a singular person.