[dishe]

you're right, that IS bizzare, especially because up until this point I was under the impression that the hardware switch PHYSICALLY SHUT OFF the WiFi radio, and no amount of software could enable it.
(all software attempts to control WiFi have been unsuccesful with the switch in the off position)

This is news to me.

Anyway, to fix your problem you need to close the data connection before closing the phone connection. Yes, forcing the phone radio to shut off will automatically close your data connection, but if you have push enabled it will continuously try to connect. If you disable it first, it will suspend push until you're ready to turn it back on.
Another thing to try would be to hit flight mode, and then enable ONLY bluetooth. Flight mode effectively shuts the data connection first for you.

By the way, airlines restrict ALL wireless communications. Using your cellphone won't crash the plane either, but they don't allow it because it would be too complicated to explain what you CAN and CAN'T do to every passenger. Bluetooth in the air IS prohibited, which is why the Moto Stereo (820s?) headphones have an optional wired attachment... listen via A2DP in the terminal, plug in the wire for "flight mode".

Sure, you could take the rules into your own hands and say "I know BT won't crash this plane", but then again you might as well just leave your phone on!