Dear  Economist,
I frequently extract large sums of money from Bozzer, my flatmate, in our regular poker game. He's convinced variance is to blame for his losses; in truth, however, he's simply terrible – and I'm simply delighted with my new watch. Am I right to exploit him in this way?

R. Casablanca

Dear Mr Casablanca,

Unless you are holding poor Bozzer's family hostage in the basement, this is a voluntary transaction between consenting adults. Presumably, he knows that he is losing money, even if he is not smart enough to work out why. And poker is lots of fun: even if he recognises that he is outclassed and the game is costing him, it may still be worth his while. After all, no customer makes a profit from going to the cinema either, but we rarely worry about that.

On that basis you have no case to answer.

However, I cannot wholeheartedly give you the absolution you seem to be seeking. You must first establish whether Bozzer is a poker addict. I'll spare you the technical details – let's just say that they probably involve hyperbolic discounting – but I can recommend an approach for dealing with a rational addict. If, away from the card table, Bozzer says that he wishes he could quit the poker habit, you must help to discourage him. Perhaps you could enlist a third party to hold on to cheques from the pair of you. She would post the money to a charity if you are ever caught gambling together.

I must also warn you that things may not be as they seem. Is Bozzer, perhaps, playing the long game?

If one evening he suggests raising the stakes, beware.

You think he's the “fish” – but he may be reeling you in.

亲爱的经济学家：

我经常和我的公寓室友博泽尔(Bozzer)玩扑克牌，而且经常从他那里赢很多钱。他深信赌注方差是他输钱的原因；但实际上，他的牌技实在是太臭了──我非常喜欢我用赢来的钱买的新表。但我用这种方法剥削他，合适吗？

读者：R.卡萨布兰卡(R. Casablanca)

亲爱的卡萨布兰卡先生：

除非你将可怜的博泽尔的家人关在地下室当人质，否则这就是两个心甘情愿的成年人之间自愿的交易。他大概知道自己输钱了，即使他没有那么聪明，想不出为什么。玩扑克牌非常有趣：即便他意识到对手技高一筹，而且赌博让他输钱，他可能仍然觉得是值得的。毕竟，去看电影的人不会因为看电影而获利，但我们却很少担心这一点。

从这个理由来看，你没有理由回答。

然而，我无法慷慨地给予你似乎正在寻求的宽恕。你首先必须搞清楚，博泽尔是否对玩扑克牌上瘾。我给你省去技术细节——让我们假设，它们可能需要双曲线贴现——但我可以给你推荐一个应付理性瘾君子的方法。如果博泽尔在牌桌之外说，他希望戒掉玩扑克牌的瘾，你必须帮他戒赌。或许你们可以招募一个第三方来保管你们俩开出的支票。如果你们再被抓住在一起赌博，她可以将这笔钱邮给一个慈善组织。

我还必须警告你，事情可能并非表面看上去那样。博泽尔是不是有可能在放长线钓大鱼呢？

如果有天晚上他建议提高赌注，你就要小心了。

你认为他是“鱼”——但说不定他正在引你上钩。      （实习编辑：顾萍）