Nothing. Except your desire not to commit a crime of taking banned items on a plane.

I can't imagine this would be effective. I highly doubt most owners of the affected Macbooks are even aware of the the FAA ban

> They even said that laptops with replaced batteries are fine...how on earth are they going to enforce that? What's stopping me from saying "Oh yeah, I got the battery serviced last month"?

Given the reactions to the Boeing news that I've heard, it would be surprising to me if people would risk jeopardising the safety of a flight to bring a personal item. However, people do remain people and act accordingly.

They were also conditioned for years with nonsense like "no cell phones on, no wifi, for the entire flight", than saw that rescinded later. Or the TSA seizing tweezers and other harmless items, then backing off later. They've been conditioned that the rules aren't always sensible, even though some clearly are.