The point of this type of assignment is to find out *what* makes people uncomfortable - and that is a doorway to finding out *why* they're uncomfortable. Really, what's wrong with eating a stranger's pie? Sure, the OP might have had some weird contagious disease that could be communicated by eating her pie, but for everyone else in the restaurant, there's no real reason it should affect them. But it does, because it's "just not done." So even though it might make the people in the restaurant confused, it doesn't harm them, and it's educational for the students performing the experiment.
My ex-BF had a similar experiment, and he and his friends chose to eat a meal while sitting on the floor in the cafeteria. Again, doesn't hurt anyone (except possibly germs from being on the floor), but other people in the cafeteria still were disturbed.
I find experiments like this fascinating. One famous one involved having a researcher dressed up to look "official" at a store that had black-and-white checkerboard floor tiles, and telling people as they were coming in that the dark tiles had just been repainted so please only step on the white tiles. People did it! I think that particular researcher was studying how people do strange things when someone in authority tells them to.
If anyone's interested (just becuase this reminded me of another fascinating experiment), check out this video
. Count the number of times the students pass a basketball.
Highlight below once you have an answer:Did you notice the guy in the gorilla suit?