Starc is an Australian who, in the wake of the the tragic death of Phillip Hughes, appears to be a slow learner about the dangers of a cricket ball. Young players also need to learn from their role models that is is not acceptable to hurl the rock-hard cherry at or near opponents.
Just as a sport like rugby is taking a much-needed new attitude to head injuries, so cricketers must change their ways in terms of respecting opponents.
Smith may have the face of a teenager, but he is proving a tough and uncompromising leader. McCullum made a serious mistake treating Smith with contempt in a Daily Mail column this year - the young Aussie rubbed McCullum's nose in the Gabba turf quite frankly.
Smith crushed New Zealand at the Gabba, and his follow up on the Starc issue has been just as impressive.
Smith said: "It was pretty disappointing. He's (Starc) done it a few times and I'm going to have a word with him when I get back down to the sheds. I don't think it was necessary at the time and hopefully he can improve and get better from that. I don't think he needs to apologise. He just needs to not do it again." Smith wants Starc to get rid of his frustration in a more acceptable way.
The 26-year-old Smith has made quite an impression in his first test, helped of course by brilliant work from his openers and a tepid, dishevelled performance from New Zealand.
Smith's grumpy demeanour in the field has already reminded observers of Allan Border, the man who led Australian cricket out of the doldrums many years ago.
And the young captain - leading the great cricket nation in his first test - has publicly slapped down one of his players, which takes some doing. There will be a lot of learning to do as Australian captain. But he is already stamping his personality on the game, and marking himself as a man in command.