Answer:
An increasingly common misconception is that "none" must always be treated as singular. The argument offered most frequently in support of this view is that "none" is a substitute for "not one," which implies singularity. In fact, "none" is just as likely to imply "not any," which implies plurality. The plural usage appears in the King James Bible and is widespread in the works of respectable writers today."
The erroneous "singular" usage of "none" was promulgated in the widely distributed 1959 edition of Strunk & White's Elements of Style, and thousands of educators mistakenly jumped on the bandwagon. This error was corrected in subsequent issues of Strunk & White, and the singular usage has been rejected by most other leading usage guides.
The New York Times stylebook addresses the issue as follows: Despite a widespread assumption that it stands for "not one," the word "none" has been construed as a plural (not any) in most contexts for centuries. H. W. Fowler's Dictionary of Modern English Usage (1926) endorsed the plural use. Make none plural except when emphasizing the idea of not one or no one - and then consider using those phrases instead.
The most sensible rule is the one that governs similar words designating a portion of something (fractions, percentages). Just as we write "some of it is" or "two-thirds of it is," we would write "none of it is." On the other hand, just as we write "some of them are" or "two-thirds of them are", we would write "none of them are."
Idiomatically, few of us would be comfortable with "None these people is happy" or "None of my friends is going with me." The sense here is plural: not any. Clearly, you would say, "None of these people are happy."
In the simplest of terms, when the sense is plural, as indicated by a plural noun or pronoun in the subsequent prepositional phrase, none is plural; when the sense is singular, as indicated by a singular noun or pronoun in the following prepositional phrase, none is singular. When the sense is plural, use plural words.
It is difficult to avoid treating none as a plural when it is modified by almost - "Almost none of the children were (not was) well-behaved." And, in constructions such as "None but a few of the students were able to complete the test," none must be treated as a plural.
Challenge:
For those who insist on none being singular, how would you deal with the following sentence:
"None of the volunteer musicians (are/is) paid for (their/its) participation."
Obviously, it is correct to use the plural "are" and "their" in this sentence. It would be ridiculous to say, "None of the volunteer musicians is paid for its participation."
Or how about this one:
"The children are all sitting at the table, but none (are/is) eating (their/its) lunch."
Again, in this example, none must be used in the plural form, "The children are all sitting at the table, but none are eating their lunch."
Can you imagine saying, "The children are all sitting at the table, but none is eating its lunch."
Neither can I.