Chessvibes is reporting that 2009 Aeroflot Open top seed Shakhryiar Mamedyarov has withdrawn from the event following his round 7 loss to Igor Kurnosov. Mamedyarov had asked the Chief Arbiter Geurt Gijssen to watch his opponent during the game, as Kurnosov was leaving the board after every move. He then made an official protest at the conclusion of the game, and withdrew from the event after no action was taken.
Now whether the accusations are true or baseless is not for me to decide, but it does identify a challenge for organisers in the future. Not so much players cheating (although that is worry enough) but the accusations that players are cheating. Anyone who has been involved in junior chess is probably already familiar with this issue, where any behaviour out of the ordinary by parents, right down to smiling at their own child, is considered 'proof' that cheating is taking place. Contract Bridge historically had similar issues, where players had to remember to hold their cards the same way, make sure they placed their cigarettes in the same corner of the ash tray etc, lest they be accused of signaling their partner.
Some are suggesting the way to deal with this is by searching every player etc etc. Hopefully it will never have to come to this. Instead the solution may instead lie with the organisers control of the playing environment. Already players are already restricted in where they can go, and what they can do (eg not leave the board when it is their move) and adequate enforcement of these rules is enough to prevent most 'suspicious' behaviour. There may have to be a more stringent area that the players must remain inside of during the game, such as playing room, designated toilet, refreshment table and arbiters desk only.
Here is the game in question. It is worth noting that (a) it was played between players rated 2724 (Mamedyarov) and 2602 (Kurnosov) and (b) it was theory up till move 16.
1. d4 Nf6 2. c4 g6 3. f3 d5 4. cxd5 Nxd5 5. e4 Nb6 6. Nc3 Bg7 7. Be3 O-O 8. Qd2 Nc6 9. O-O-O f5 10. h4 fxe4 11. h5 gxh5 12. d5 Ne5 13. Bh6 Nec4 14. Qg5 Rf7 15. Bxc4 Nxc4 16. Rd4 Qd6N 17. Bxg7 Rxg7 18. Qxh5 Qf4+ 19. Kb1 Bf5 20. fxe4 Bg4 21. Nge2 Qd2 0-1