I don't think this will be much of an issue, they can always check your bags before you enter the plane and, if they see a laptop, they will turn you around. It is another matter that this ban will hit the companies hard. For example, Etihad Airways used to be my favorite flight company. Now that I cannot carry a laptop on the plane because of the silly ban (and I'm not careless enough to put a laptop in the baggage, given how much the workers will thrash it around), I will simply resort to flying with some other company, say, Air China, which I like as well. Many Americans and foreigners flying to America will switch to more convenient airlines, and, aside from Etihad and others losing a lot of income, the ban won't have any effect on anything.