Q. Is there a rule governing the use of commas in a compound imperative sentence where the subject is implied? For example: “[You] Take the documents to the incinerator and follow safety guidelines during disposal” or “[You] Take the documents to the incinerator, and (you) follow safety guidelines during disposal.” Technically, these are both independent clauses. Is there any official rule that states whether the implied you exists only at the beginning of the first clause? Is this one of those situations that is never covered because it doesn’t matter?
A. No official rule can tell us what a writer was thinking, but when we read “Do X and do Y,” a comma before and implies two independent clauses: “[You] do X, and [you] do Y.” The lack of a comma implies a compound verb: “[You] do X and do Y.” CMOS covers this type of comma at 6.28–29, but as you guessed, much of the time it doesn’t matter.