Quoting Feynman once, twice, thrice.

I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.

The first principle is that you must not fool yourself - and you are the easiest person to fool.

For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.

These are all quotes attributed to Richard Feynman and they all came to mind when thinking about data retention and ID card proposals.