To take this from a flip perspective and using the NEXUS reference as an example, I do travel to the United States frequently, and to make my life and my travel easier, I recognize I am going into another sovereign country and I have to respect their laws and their rules—much the same way anyone coming into Canada would. For all that, to make my life easier, I realize that I need to give up a part of my individuality, in this case fingerprints, which I had already given for a previous visa, and an iris scan.
So on that point, I do not have an issue with biometrics being used, because it is used against a larger database to confirm, number one, my identity, but also to confirm that I'm there for a legitimate intent. So when I go down to the United States, I'm going there for a legitimate intent, and this is why I use a NEXUS card.
The flip side of that is that if the NEXUS system was simply just to identify who I am by matching biometrics to iris, or to fingerprints, if there was no database to compare it against, my card can say Joe Smith, and when I show up to a border it will say Joe Smith, and yes, this is Joe Smith. That's the issue I have with biometrics.