A recent labor-law case (O’Connor v. Oakhurst Dairy) turned on the absence of the Oxford Comma. The Oxford Comma is the last comma in a series. For example, guests at my wedding included my parents, Winston Churchill, and Vladimir Lenin. Omitting the comma would cast the sentence as “guests at my wedding included my parents, Winston Churchill and Vladimir Lenin.” Depending on how you read that, I could have an interesting family.
The employer did not have to pay minimum wage to certain employees if they came within an exemption in the law. The exemption applies to employees engaged in canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of certain products.
The subject employees worked in distribution but they did no packing. Are they exempt? That depends on whether “packing” modifies only shipment or both shipment and distribution. It’s hard to say from the language above.
The court fell back on the rule that, in cases of ambiguity, such exemptions should be construed in favor of the employee. Too bad for the employer.
Of course, had there been a comma after “shipment,” it would have been clear that the exemption did not apply. No lawsuit would have been necessary and the parties need not have spent tens of thousands of dollars and who knows how many years to get this result. To be sure the employer won such a case, the drafter would have had to rephrase the sentence, not an onerous task.
Again, the best that can be said for omitting the Oxford Comma is that the omission is not always ambiguous. So if your goal is to avoid ambiguity some of the time, by all means omit the Oxford Comma.