Any player who does not shake hands with the opponent (or greets the opponent in a normal social manner in accordance with the conventional rules of their society) before the game starts in a FIDE tournament or during a FIDE match (and does not do it after being asked to do so by the arbiter) or deliberately insults his/her opponent or the officials of the event, will immediately and finally lose the relevant game.
Bad manners maybe, in certain circumstances, but a loss of game? They have got to be joking! Never mind that there may be perfectly legit circumstances for one to refuse to shake an opponent's hand. What if my opponent went to the toilet and I saw that he didn't wash his hands? Or how about Rogers' example in his column of former Aussie chess champion (in 1957 with S. Lazare) Karlis Ozols who was later discovered to be a former Latvian SS officer? "[O]ne could understand", GM Rogers writes, "if some of his Melbourne opponents found shaking his hand before a game a step too far".