Oxford comma drama

Are dairy delivery drivers exempt from Maine's overtime law? No, because of a missing comma – the one known as the Oxford comma. Here's the first paragraph of O'Connor v. Oakhurst Dairy (1st Cir 03/13/2017):

For want of a comma, we have this case. It arises from a dispute between a Maine dairy company and its delivery drivers, and it concerns the scope of an exemption from Maine's overtime law. 26 M.R.S.A. § 664(3). Specifically, if that exemption used a serial comma to mark off the last of the activities that it lists, then the exemption would clearly encompass an activity that the drivers perform. And, in that event, the drivers would plainly fall within the exemption and thus outside the overtime law's protection. But, as it happens, there is no serial comma to be found in the exemption's list of activities, thus leading to this dispute over whether the drivers fall within the exemption from the overtime law or not.

Maine's overtime law says it does not apply to:

The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of:
  (1) Agricultural produce;
  (2) Meat and fish product; and
  (3) Perishable foods

So what does "packing for shipment or distribution" mean? Dairy drivers perform distribution, but they do not perform packing for distribution. If you stick in a comma just before the words "or distribution," then it would be clear that the drivers were exempt. But the court pointed out that lack of a comma simply makes the whole thing ambiguous, and ambiguities need to be resolved in favor of the employees.