VAR and AI: what the machine does and what the person decides
Although VAR is talked about as if it were a machine, VAR (video assistant referee) is a team of people who review the video and advise the referee. It is not an artificial intelligence.
AI comes into some of the tools that support it. The best example is semi-automated offside: cameras and computer vision track the players and a sensor in the ball marks the instant of the pass, to calculate the offside position. There are also tracking systems that help locate the ball and the players in the image.
Under the IFAB protocol, VAR only steps in for goals, penalties, direct red cards and mistaken identity, and only corrects a clear and obvious error. Judgement calls, such as whether a foul deserves a card, are made by a person.
The underlying question is what we want a machine to decide: what can be measured (a line, a position), yes; what depends on interpretation is better left to a person.