Last year I jokingly suggested that FIDE should look at removing the right to resign a game from the rules of the game. Less than a year later, someone has done exactly that.
Not FIDE as such, but the Iranian organisers of the "Mate of the King" match between GM Anatoly Karpov and GM Ghaem Maghami. In the tournament regulations players were not allowed to offer or agree to draws, and were forbidden to resign. In the words of the organisers "all games should continue until the last playable move on the board". In a losing position players were required to keep moving until mate. Draws were by stalemate, 50 moves and repetition only.
Of course their is one big hole in the "no resigning" rule. As the games were being played under a time limit, a losing player could simply let their clock run down. Simply getting up and walking off may be another option, although you aren't supposed to leave the board while it is your move.
Anyway it seemed an interesting experiment although I could hardly see the concept catching on. As for the match, home town boy Ghaem Maghami won the blitz match 6.5-5.5 after the Classical and Rapid matches were both drawn 2-2. And despite the regulations there were 5 games that ended in draws, all by repetition, with one finishing as early as the 32nd move.