Ok, so why am I told it works in Europe? You've actually tried it here, including the (I think very important) rule that it is made clear the banker will not be counting, and if you underpay, you are stiffing a friend? As it was explained to me, this is what makes the difference and causes people to overpay.

There certainly are people willing to overpay. With Div-N, sometimes we see a short pot -- which can't be any sort of mistake, it is probably an anonymous protest by somebody who ordered cheap -- there are always folks willing to chip in a bit more, perhaps because they feel they got a deal with Div-N. But fairly often there's a fat pot, which goes to the restaurant, or perhaps from time to time to the person who wants to wield their card.

(Some more comments on Div-N added to the main article.)