I have not read this article, but RMS surely would argue that without a completely open stack, you cannot really know what airplane mode does. You can check that it doesn't broadcast at any moment you want to check that, but how do you know it doesn't switch on for 5 seconds every 4 days, 13 hours, and 52 seconds, except for Thursdays or in March? Also, how do you know that it isn't listening for secret commands all the time?