During play itself, the rules of a sport may be abused to favour one player or team. This may include unsanctioned movements, violence to other players, intimidation of opponents, and concealment of such infringements from any referee. In preparation for the sport there are many methods of rendering its practice unfair. These may include use of drugs, bribery of players or the referee, intimidation and violence. Many such practices are used because of the money that can be made from sport, either through gambling, media rights or advertising sponsorship. Secret agreements may be made with many of those involved (whether players, referees, organizers, or sponsors) to ensure that one party wins or loses and that all benefit financially from such unfair practices. The opportunities in this respect have attracted considerable interest from organized crime.
Media publicity is regularly given to instances of bribery of players, teams, or referees. In the case of a sport like professional wrestling, it is widely accepted that the outcome is fixed in advance, even contractually. In relation to the Olympic Games, much attention has been given to the incidence of drug abuse, notably steroids. In preparation for the 1994 Winter Olympics, one ice skater was physically damaged by the former husband of another. The Olympic Games has also seen examples of concealment of sex by participants seeking to be classified as women.