So, if the SE sites discourage link-and-run (or rather, encourage down-voting of LAR answers), why isn't this in the FAQ? 

Earlier Meta discussions, showing that LAR is discouraged.
http://meta.stackoverflow.com/questions/38001/statistics-current-ratio-of-link-and-run-on-the-stack-exchange-network

http://meta.stackoverflow.com/questions/37968/reduce-posting-of-linking-hit-and-runs-answers

Example of me assuming that such was in the FAQ, and now looking like a jerk (possibly because I'm a jerk.)

http://serverfault.com/questions/394762/publish-jpg-file-as-a-screensaver-via-gpo

Edit - I'm a silly man. This is actually in the FAQ, but you have to expand one of the answers. http://serverfault.com/faq#deletion