Ask Slashdot: How to Determine If One Is on a Watchlist?

An anonymous reader writes: On Slashdot, we joke about it all the time: "I did a Google search for 'pressure cooker' and I connected a bunch of times to the Tor network to download some Linux distribution .torrent files... I must be on some sort of watchlist now." There have been news articles about people being questioned in airports and given special attention for being political activists. How can one determine is one is on a watchlist of some sort? Are there any Slashdot users who are knowingly on a watchlist? What sort of suspicious special attention have you received?