This is an amazingly ridiculous line of reasoning. By this measure, they could never use the "maximum penalty" because there is always the chance that the next guy will do something worse. Proportionality matters, but once you are a three time offender of a fairly obvious infraction that can be easily avoided and has no place in the action of the game, you can't be protected against further punishment simply because somebody thinks that one day some other dude might actually follow through on the bite and rip off an ear or something. That's absurd.