In the 1970s the FBI tried to bully librarians into providing patron information -- who reads what -- to them. The general response (including that of those dear little old bun-haired ladies) was, "F**k you, Jack -- get a warrant!" State legislators took note and, as far as I know, passed laws in every state guaranteeing the privacy of library records (unless there was a court order or warrant). The FBI gave up trying to bully librarians.

The Patriot Act still requires a warrant/court order, but makes it far, far easier to get one. Moreover, it makes it possible to use library records as part of a fishing expedition, NOT a search for evidence of an actual crime.

"Whatever you say say nothin'
When you talk about you know what..."