@ alexlaw: All I can recall (and I might not even be correct) was that Andy Soltis mentioned it in his "Chess to Enjoy" column many years ago in Chess Life.
Resigning OTB games

She notes in her video that even after R1e2 that black is still better. I did not confirm this with an engine though.

Once I put my hand out to resign only to discover that my opponent had run out of time on the clock and that I won the game in a hopeless position.

Bill Wahl has some good advice on the topic:
http://www.geocities.com/siliconvalley/lab/7378/resign.htm

Bill Wahl has some good advice on the topic:
http://www.geocities.cI have never seen a chessplayer whose eyes were not gleaming with murderous revenge after losing. om/siliconvalley/lab/7378/resign.htm
"I have never seen a chess player whose eyes were not gleaming with murderous revenge after losing. "
he obviously haven't played in my area where some chess players are babble happy about losing almost on Valium. why show up playing if losing or winning doesn't mean anything at all? I want an opponent who are cares about the game enough to make it a fight.
we are humans not robots - to err is human - and if that means being a bad loser sometimes. you give all you got in a game.

Bill Wahl has some good advice on the topic:
"For hypermodern players, both arms are extended towards the opponent. The hands stay open but placed around the neck of the opponent who is then shaken vigorously until the opponent's face turns a dark blue color. Usually, the tournament director intervenes at this point to make sure the game is over."
magnus lost to Queen Kosteniuk http://www.youtube.com/watch?v=WeyXKTVYenA at 7:36 or something ...."by leaving the board he showed that he resign." it almost looks as if magnus spits her in the face.
Interesting!