I should have been one of those people who guesses other people's weight at the carnival. I was sitting on the subway the other day, trying to size people up and i seemed to be pretty much right on. I asked a couple of people if i was right, and i got some very strange looks.
I did however find that if i phrased my questions appropriately, it came across as not as akward or bizarre. When i asked people outright what they weighed, they were either offended or looked at me like I was nuts. When i suggested that they looked like someone I knew, or was trying to purchase a gift for, they were more willing to share their weight with me.
the outcome of this venture was that I figured out I could probably take out about 30% of the people that I asked in a wrestling match :)