It would be controversial, depending on what country of jurisdiction was supposed to be applied on. Meeting a ceiling of maximum wager for high rollers would be translated to setting a ceiling to the earnings and profits of casinos. Time it would be more favourable in terms of morality for gamblers to be fully aware and not drunk while gambling, to make them understand the degree of the risks and the potential consequences on their lives.
Ironically, it would be like setting a ceiling on the amount of beers or the numbers of cigarettes people is supposed to consume, at least, in countries like the United States, those laws could be perceived as an direct attack on the basic rights of each citizens.
Though, I am not against increasing awareness on problem gambling.
Not sure about limiting high rollers but I have surely seen a maximum cap on betting on one of the sites.
One point to notice is that Watanabe was losing around $5 million dollars a day and so it took him so many months to lose what he had.
So it's not like he wasn't aware of what he was doing. Even if he was drunk while gambling, he would have noticed that he has spent millions in gambling.
He did have the chance to stop himself but didn't. May be was addicted to gambling or he deliberately wanted to lose it all.
Well, It could be, still I am not 100% sure whether he was aware on what he was doing. I have never been addicted to gambling and I am hoping never to be, but in my personal point of view, those who suffer from problem gambling do not actually want to "lose it all" or become penniless from his actions, they actually believe or feels there is no a choice for them, they need to continue to gamble as long as they have a dollar in their pockets. It is a driving force from within which forces them to burn their budget, always seeking for thrill or for the chance to get part of their money back.
It does not matter how rich an individual is, losing 5 million daily is such a rapid and deteriorating state which makes me believe whoever happens to be in it does not have any control over their actions or thoughts.
Though, Not that I am expecting someone addicted to anything to be reasonable...