Nothing to prove here. It is a fact that they tampered with the ball using bottle caps and other objects. It is extremely naive to think that just because they were not caught in the act means that they did not use underhand tactics.
Since reverse-swing became mainstream, all teams have been guilty of tampering. However, it is harder to get away with it now because of technology.
Nonetheless, they did admit to ball-tampering.
https://www.independent.co.uk/sport...rowing-light-on-a-touchy-subject-1434755.html
In 2000, Waqar became the first player ever to be fined for tampering.
http://www.espncricinfo.com/ci/content/story/88784.html
The English and the rest did not know how to tamper with the ball to make it reverse back in the 80's and 90's, which is why they routinely accused Pakistani bowlers of cheating. The most famous example was in the summer of 1992 when Wasim and Waqar were too hot to handle for them.
However, now that all teams have learned how to do it, the players have toned down in terms of accusations. All teams accept the fact that these things happen. Faf was caught twice, once under Smith and once under Amla. How often is he labeled a cheat?
If the umpire catches, you are in trouble. If not, you get on with it. That is how it works nowadays.
Nonetheless, you still have to be a good bowler to make use of reverse-swing. It does not hamper your legacy.
The overreaction in this thread is because of Australia's reputation as the bad boy of cricket. Why should Smith face harsh punishment when other captains have gotten away with less? Why hasn't a repeat offender like Faf received a lengthy ban? Why weren't his captains, Smith and Amla, stripped of captaincy?
Smith and Bancroft should be and will be punished. However, it should be in line with the punishments that the previous offenders have received. Ball-tampering is a reality and the ICC cannot do anything to eradicate it. You either get away with it, or you are unlucky enough to get caught.