Gambling is not addicting by itself, it's not that you can't gamble just for fun from time to time without becoming addicted. Greed of those who gamble is making it addicting mostly. Do not be greedy and gambling will not be addicting.
Well I think that is not a problem because if a person is really greedy I think he is already addicted to gambling and not controlling his bets is the one problem a gambler can make because of his addiction he became greedy with every bets he make.
He will become more greedy if wins it big in first round, he will be having a strong feeling that he can win again and that greediness will lead him to the addiction.