I have heard several people say, "Well, I've got nothing to hide," when concerns over national id cards are expressed.
Here's a dozen of things I hear when people make such a statement:
1. "I have no concept of history."
2. "I don't understand the spirit of the Constitution."
3. "I have no regard for America's heritage of freedom."
4. "I don't value the blood shed in generations past fighting totalitarianism in other parts of the world."
5. "I trust government as inherently good with no possiblity of going wrong."
6. "I have little self-worth."
7. "I'll let our leaders do nothing to stop illegal immigration, but it's fine for me to be 'tagged.'"
8. "I like being monitored wherever I go."
9. "I want to be booked like a criminal--even without having committed a crime."
10. "I've never read the 4th Amendment."
11. "Let's not do the hard work or make tough decisions to root out terror. Just sell out freedom for security..."
12. "The Constitution cannot stand in the Age of Terror."
13. "I want identity theft to be easier by centralizing my life's information." (A baker's dozen :)