I can verify they do in fact receive (if not transmit) data - I worked an immersive art project that had 100 Samsung cell phones that were in airplane mode, and we found out the hard and noisy way that they were still able to receive emergency and AMBER alerts (U.S. alerts that notify of potential child abductions).

They need to add possibility to disactivate the hardware components, in order to save battery power (in addition to disabling the features you mention).