Imagine this. At a critical moment in a finely balanced Ashes Test or India-Australia match, a batsman is given out lbw to a ball that nips back into him. He proceeds to walk a few steps towards his dressing room, only to turn abruptly and ask for a review. Replays show ball striking pad outside off stump. The umpire has to reverse his decision.
Imagine the uproar from the opposition, the media noise, and the spillover of all that bad blood into the remainder of the series.
There was no uproar or bad blood when Dilruwan Perera survived an lbw decision in this manner on Sunday at Eden Gardens, in a Test match that was delicately poised at that point. Sri Lanka denied that there had been any signal from the dressing room to Dilruwan. Their statement said he had turned around because he heard Rangana Herath, at the other end, ask Nigel Llong whether Sri Lanka had any reviews left, and heard Llong reply in the affirmative. India didn't make a fuss about it either.
Imagine this now. Almost exactly the same thing happens, in a finely balanced Ashes Test or India-Australia match, except this time the on-field umpire has spotted someone in the dressing room gesturing to the batsman to turn around and ask for a review. The umpire tells the batsman he cannot review, and he walks off. Replays, once again, show the ball striking back pad outside off stump.
In this instance, has the DRS protocol prevented the correct decision from being arrived at?
Extend the argument a little further: is it necessarily wrong for a batsman or fielding team to seek assistance from the dressing room, if in the process the right decision can be made?
Given that the review must be asked for within 15 seconds of the original decision, it doesn't allow enough time for the occupants of the dressing room to have watched replays. They would have watched the action live, and after about a second's delay on TV, from a behind-the-bowler view not available to anyone on the field. Would that not mean they are better placed to advise the batsman or fielding captain on whether to take a review than the non-striker or wicketkeeper?
The question leads us to the tension that lies at the heart of the Decision Review System.
We hear it often, and the ICC maintains this position, that the DRS exists in order to minimise "howlers", or obviously wrong decisions - an inside-edge onto pad that the umpire has missed, or a caught-behind given when the ball has brushed elbow guard rather than glove.
With that in mind, it's clear why players aren't allowed to take dressing-room assistance while deciding whether to review. It's unlikely a batsman would not know that he's inside-edged onto pad, or strongly suspect that the ball pitched outside leg stump. In these cases, the batsman really wouldn't need to look at the dressing room for help.
In Dilruwan's case, the decision was marginal: the ball struck his back pad half an inch outside off stump. In the old days before DRS, commentators would call it a close but fair decision, and leave it at that.
Players, however, don't use the DRS only to reverse obviously wrong decisions. The bulk of reviews are of marginal calls, made on the basis of hope rather than belief: balls that may or may not have hit or off stump or clipped the bails; balls that struck a batsman's pad while he was moving across the stumps, where impact could have occurred in line or just outside; balls that could have pitched on or outside leg stump, give or take a tiny fraction.
As a result, most of the ICC's tinkering with the DRS has focused on marginal decisions. Last year, the definition of "hitting the stumps" for ball-tracking calls was amended, which meant some marginal lbw reviews that earlier reverted to the on-field umpire's call now fell within the realms of definitely being out. This year, teams have been allowed to retain reviews that return an "umpire's call" verdict.
The latter decision - only mildly counterbalanced by the decision to end the topping-up of reviews at the 80-over mark in Test cricket - directly incentivises players to review marginal calls, moving the DRS another step away from its stated aim.
In this climate, therefore, it seems arbitrary that players can't ask their dressing room for help with reviews. When batsmen can question entirely reasonable umpiring decisions because they are now at less risk of losing reviews, why not let them get some extra help while they're at it? It could even open up the job market for specialist DRS consultants.