From my initial research, there are no safeguards - agents are on the honor system. A person won't ever know if they've had their records subpoenaed so they won't even be able to challenge it.
The Patriot Act was signed on October 26,2001. It is as of today December 20, 2005. Over 4 years. Where is your beef?
All that trolling and no case?
http://www.freerepublic.com/focus/f-news/1544717/posts