My thoughts are what would we want to happen if it was a team doing it against us? (& they have numerous times).
Now that Smith has owned up to it, then he MUST be stripped of the captaincy & never captain Australia again. For being the leader & asking Bancroft to do it, CA should suspend he for 5 tests & Bancroft 3 Tests. The ICC aren't usually this hard on players, but Australia needs to send a message to the World & our own players that we will not tolerate it & anyone caught doing it will be punished severely no matter who it is.
They have brought the whole country into disrepute by doing this.