I fixed a fragment today in a book I'm editing, and did consider, "Maybe this is voice!" That is not, however, an argument that sways me all that much. I mean, if the writer's voice is good, I notice. :) And I notice when a fragment ISN'T contributing to that voice, as here:
(Of course, I'm changing the wording, just keeping the structure.)
She knew very well the requirements of her job. Such as typing, filing, and reconciling receipts.
That "such as" phrase is, of course, a fragment, and immediately I replaced the period with a comma:
She knew very well her job requirements, such as typing, filing, and reconciling receipts.
The "such as" is only an elaboration of "requirements." (Notice, btw, I just as immediately flipped to get "job requirements," first because it's more concise, reducing a prepositional phrase to a single-word adjective, and second because that puts "requirements," the modified noun, right next to the modifying phrase.) There is no advantage I can see for breaking off "such as" into its own sentence. There's nothing truncated, no elliptical word missing-- just a period instead of a comma. Nothing is gained by fragmenting that modifier, and much is lost, like coherence and correctness. The fragment annoys without contributing anything.
Actually, I might be okay if there were no "such as," which is, of course, a conjunction whose whole purpose is to conjoin examples to the thing exemplified. Let's try it just with the list:
She knew very well her job requirements. Typing, filing, and reconciling receipts.
Well, you know, I'd still generally put that into the same sentence, with a colon (if this was formalish) or a dash (if informalish) or a comma if I've been using too many dashes. :)
And in fact, I think I'd only take it out of the sentence if there was some surprise or irony, which is definitely not in the original sentence. Why bother call attention to anything that isn't attention-getting? Remember, anything non-standard is going to call attention to itself, so make it worthy of the attention, or do it the standard way. (All sentences have meaning, or should, but I think non-standardness is best reserved for a twist or dramatic moment. Remember, the more you use non-standard, the less impact it will have.)
So let's make that sentence more potent, just to illustrate:
She knew very well the requirements of her job. Typing, filing, and covering up the boss's embezzlement.
Hmm. I have to say, I'd probably go with a colon or dash, because the irony is stronger if we have the expected (the main clause) actually conjoined to the punchline.
She knew very well the requirements of her job: typing, filing, and covering up the boss's embezzlement.
Anyway, the conclusion is: It's all about context. And that context includes not only the whole standards issue, but also the meaning of the sentence, the import of fragment-ness, and the voice of the narrator (or author, if authorial voice is in control here).
I think, however, that the fragmentation itself should add some meaning, as it does, for instance, if it emphasizes the punchline, adds a staccato rhythm to the paragraph, or suggests the fragmentation of reality going on inside the narrator.
But fragments should never be the default. There should always be something added by the very fragmentation.