Older readers, even those who are not really into sport, will remember the phrase "It's not cricket!" It meant, "It's not right" or "It's not fair". Cricket is not only a game with rules but with a long tradition of sportsmanship whereby you behaved in a way that upheld the rules; your behaviour was always righteous.
When playing the game of cricket if you knew you had nicked the ball (touched it with your bat) and it was caught by the wicket-keeper or another fielder, you immediately walked to the pavilion, even if the umpire had not spotted it. But that's not so with today's cricketers.