An important aspect of the Laws of the Game that applies at all levels is that a referee cannot change a restart decision even if they realise it is incorrect after play is back underway. So, once the corner is taken and play is live, the game must continue. Thus if the new laws are implemented at the World Cup next year, every corner will have to be reviewed by the VAR - although in the majority of cases the decision will be obvious.
Fans will be eager to see if and when FIFA gets the nod to bring in the rule changes in VAR. Before that, they must extensively trial the methods to make sure their plan is foolproof.