Lest you think this is merely an academic problem, I ran into a catastrophic, real-world case where it mattered.

I lost a notebook at a big box store. It had major sentimental value to me[1]. I called their Lost & Found and asked if someone had returned a green notebook. They insisted they didn't have one.

When I went to the store in person, they had it. Because they felt that it wasn't green, but blue. And (presumably) that no one would describe it as green, so they should return False for "matches what a green-notebook-seeking human wants?"

Here's the notebook: http://i.imgur.com/AlQAZBJ.jpg

So, for the linked question: whenever answering a question, you need to know why you're answering it. It affects the answer! Consider these purposes:

1) "I want to know if other people will agree that this is a green notebook."

2) "I want to know if I should say this definitely-doesn't-match when someone comes looking for a green notebook."

3) "I want to know if this notebook reflects almost entirely green light."

Case 2 is the one I was interested in. In that case, 10% respondents are enough to say "hey, that might be a match".

[1] I know, "you shouldn't have brought it out with you".