Why did you have to call this "last tip?" Now you have us all in tears again, Rudi.
I'm glad you mentioned that unmetered cabs are common in developing countries, since that description also fits Washington, DC, where cabs use a "zone" system. A map of the zones and the fares (which depend on how many zones the trip touches) is posted in the back seat of each cab, but I dare anyone who's not a native or regular visitor (and many who are) to figure out what any fare should be. That's especially true when the driver doesn't necessarily take the shortest route from point A to point B, thus managing to cross into an extra zone or two on the way (all it takes is a block to add an extra zone to the legitimate fare). I'll take a meter any day. Of course, there was the time I came out of Penn Station in Manhattan, climbed in a cab and asked to take me to my hotel (I think it was the Omni at the time). He put down the flag, did a U-turn, stopped, let me out and collected the minimum fare. The hotel was right across the street.