If a tree falls in a forest, and no one is there to hear it, does it make a sound? Or, if a tree falls in a forest, and no one is there to hear it, but someone can see it on CC TV, does it make a sound? CC TV carries only video. It shows the tree falling. [For a nice introduction to George Berkeley’s thought experiment, see this]
This is basically what happened with Kohli’s fake fielding situation. Under Law 41.5, Kohli’s actions were clearly questionable. He did wilfully attempt to distract or deceive the non-striker after the striker had received the ball. That he may not have seen it that way, or have intended it that way, is irrelevant. The Law evaluates actions and their effects, not intent. And Kohli’s action was deceptive - he pretended to throw down the stumps at the bowler’s end after first pretending to intercept Arshdeep Singh’s throw while he did not have the ball.
But here’s the rub. ESPCricinfo reports that “At the time, it went unnoticed in the field as the on-field umpires, Marais Erasmus and Chris Brown, didn't take action, and the Bangladesh batters - Najmul Hossain Shanto was the other - didn't point it out.”
So, the question is, did the non-striker notice it? If the non-striker didn’t notice it, it cannot very well be considered a deceptive action. It is not clear from the reporting whether he noticed the action and didn’t think it noteworthy at the time, or whether he didn’t notice the action at all.

Technically, the Bangladesh wicket-keeper Nurul Hasan is right. His team’s awareness of every minute detail of the Law is something Kohli himself specializes in and would appreciate in other players (notice Kohli’s awareness of the bouncer restrictions).
Did the umpires miss it? The answer to that depends on what ‘it’ is.
If ‘it’ refers to Kohli’s actions, then they didn’t miss it. The square leg umpire was standing at point and was following the ball. Kohli was right there in front of him pretending to catch the ball and throw down the bowler’s stumps.
If ‘it’ refers to action which “attempted to cause such a distraction, deception or obstruction”, then the umpires have to see some evidence of the action having an effect. This was not available in this case. The batters were not attempting anything which was stymied or obstructed due to Kohli’s actions.
The technical answer to Berkeley’s question is that sound is vibration in the air which is transmitted to our ears. If there are no ears to receive the sound, then no transmission has occurred.
So, in summary, if you subscribe to the anthropic principle, then Kohli did not breach Law 41.4. Under this principle, for the sound to have occurred, conditions for both the making and transmission of the sound (i.e. the presence of a receiver) must be satisfied. But if you believe that making a sound is both necessary and sufficient for the sound to have occured, then under such a view, Kohli was dead to rights guilty of unfair play.
The really interesting question is what the umpires would have had to do if the batsmen had indicated that Kohli had tried to distract them. In that case, I think the law would have been enforced.
Sadly for Bangladesh, this would not mean 5 penalty runs because it would be first offence. Rohit Sharma would receive an official warning that a second breach would mean a five run penalty.
Nurul Hasan is right that Kohli may have breached the Law, but he’s wrong when he says “It could have been a five-run penalty”. Even if that action was considered Unfair Play under Law 41, it would not have been a five-run penalty.
Mass. Thanks for clarifying it. And the 5 runs BS by BAN is doused now