Coconut mystery solved
I finally got around to looking up that student essay's reference to medieval peasants drinking from coconuts. Here's what the source actually said.

Many other types of drinking vessels were in use, made of various materials in silver-gilt mounts. These were chiefly coconut and nautilus and other shells. Coconut was believed, towards the end of the Middle Ages, to have medicinal properties, and remained popular as a material for drinking vessels up to the middle of the sixteenth century or even later. The first English reference is in a will of 1259.*

There's a photo plate of a fancy silver-trimmed hanap made from a coconut. The context of the passage is a discussion of the furnishings of aristocratic tables. There's no way a reasonably literate student could assume that this passage on the exotic tableware of the rich and famous applied to medieval peasants.

Grr. I hate it when the little stinkers try to misrepresent their research. If I'd looked up that passage sooner, I would have written her some stern comments about what happens to people who try to pull that stunt in the so-called real world.

_{*Gerard Brett, Dinner is Served: A History of Dining in England, 1400-1900 (London: Rupert Hart-Davis, 1968), 75.}