Protected events
In the UK, the regulations set out in the Ofcom Code on Sports and Other Listed and Designated Events dictate that some sporting events must have coverage made available to free-to-air channels. "Category A" events, including the Olympic Games, FIFA World Cup and Cricket World Cup should be available live, while "Category B" events such as all test cricket played in England and the Commonwealth Games should be available as highlights or with a short delay.
A similar concept applies in Italy (law 8/99) and Australia (anti-siphoning law) to some important sport events.
In contrast, no law in the United States or Canada dictates that any given sporting event must broadcast over the air. In both countries, the general trend has been for the major leagues to slowly migrate their broadcasts to subscription channels, a process that has reached virtually every sport as broadcasts that historically have been free-to-air are now available only by subscription. Nevertheless, the National Football League has an internal policy requiring that its partners broadcast every game over the air, in the very least, in the visiting team's home market (and, if the game sells out, the home team's market as well), and the league's conference championships and league championship have always been carried on a terrestrial broadcaster.