Yes, me for one. But as you say if it took place in real life there's a complicating psychological factor. If you chose £4 you may well swap because it is not a significant amount. If the amount was £32,768 you would probably keep it because losing half that is significant. However, if it was £20,000,000 you might well swap again because £10,000,000 is more than most people are likely to have in one go it is worth the risk again