It was an absolute shocker.
In an ideal world, Stevic would come out and say there wasn't really anything in it, that he was a bit too keyed up on the night, and in any event, no-one wants to see such soft reversals during a prelim.
That said, the Hawks bloke had no reason to expect contact, Ballas saw him the whole way, and gave him a cheeky one. The AFL is trying to get rid of this stuff, so, Stevic can't say the above. He can't say it's not a free kick (technically it's there), he won't say he was too wound up because that would admit he is a bad ump, and he can't say that there should be a different set of rules for H&A and finals - even though it's what everyone expects.
He should have just said nothing.
As for Ballas, he has escaped blame in this. He had absolutely nothing to gain by this, and it gave the umps the chance to pay a free kick and swing momentum. Either flatten the bloke, or just play the ball.