Ravichandran Ashwin caught the shoulder of Peter Siddle's forward prod and the ball looped to Ravindra Jadeja at 2nd slip late in Australia's second innings. Law 27(1) specifies that
Neither umpire shall give a batsman out, even though he may be out under the Laws, unless appealed to by a fielder. This shall not debar a batsman who is out under any of the Laws from leaving his wicket without an appeal having been made.When is an appeal made? Here, the use of the review brings with it an interesting conundrum. When a fielding side asks the Umpire "How's that", it has traditionally meant something as follows: "We think that's out, how do you see it?" Now, if some players appeal and ask "How's that", but the fielder who was actually involved in the play (who took the catch, for example), is not sure, then how is it an appeal?
In the case of the appeal against Siddle, since the Umpire asked for the catch to be reviewed, it means that Jadeja claimed the catch. But in this instance, he palpably didn't. He shrugged his shoulders, as if to say "I'm not sure about this". Why should an Umpire even go up for review when the fielder who caught the ball isn't sure?
The opportunity of review (player review as well as umpire review) has begun to unravel concepts that were apparently settled. Before the advent of the review, the demarcations were clear. The fielding side would claim a dismissal (and if the fielder said he wasn't sure, then that was it, it stayed not out), and the Umpire would rule on that claim. Now, the standards for claiming the dismissal have softened to the point where the fielding side only has to indicate suspicion of dismissal in order to gain a review.
The case of Michael Clarke's LBW in the 2nd innings at Chepauk showed that looking at an event through a different type of sampling (super slow motion) reveals different facts about the event, and that sometimes, these facts can imply conclusions that are at odds with the ones reached confidently in real time. The case of Jadeja's non-appeal against Siddle reveals that the very availability of review has begun to change the definition of the appeal itself.
Umpires would do well to require fielding sides to commit to claiming a dismissal. While batsmen rarely walk, and have accepted almost universally after the cynical Australian fashion (championed by Ian Chappell) that umpires are there to make decisions (in this series, both Sachin Tendulkar and Michael Clarke have not walked for caught dismissals which they could not possibly have not known about), fielders are still by and large sincere. As Jadeja showed, they tend to make honest claims. The review enables everyone concerned to by pass this honesty.