How can there EVER be a time to not worry about commas? Grrrrrrrr.

If the writer wants to be sure of clarity, no.

As the grammarian Tredinnick puts it:
"The comma as pause has been oversold and under-explained. We need a smarter notion. Punctuation lets a reader rest where we, in the telling would rest, and it tells the reader where and how long to wait. The purpose of waiting is to notice the relationship between the parts as the reader passes among them; the waiting and the breathing and the noticing expose the structure of the short story piecing itself together around the reader. Punctuation points to the hinges, the joins and the breaks. It tells the listener, through the different kinds of silence it invokes, how to take the sentence’s bends.

Punctuation marks off, for instance, the subordinate clause from the main; it encloses parenthetic expressions; it separates words or phrases in a list; it marries the appositive to the subject or object it complements; it ties two main clauses together in a compound; it introduces an explanation or an aside’ it brackets definitions and scientific names.

Punctuation helps the words do what they can’t without a speaker. Punctuation let’s a sentence talk, and let’s the reader hear it, almost as though it were being spoken."