I would bet that more than 50% of devices on planes are already left on for takeoff and landing. The only thing being turned off is the screen.

You're making an awfully big assumption about this not standing up in court in Korea. Do you Have any idea what trademark law is like in Korea? (This is an honest question, I certainly don't know.)

I just took a look at the press release about the settlement of trademark dispute in the United States. The guy who tried to trademark Linux here at least had his filing fees returned, and since the rest of the details of the settlement were not disclosed, he may even have earned some cash on the whole deal.