ROFL I did this test on a bunch of 1st gen iPhones.
Put your iPhone on Airplane mode.
Go to WiFi. Enable it.
Connect to your favorite network.
Wasn't Airplane mode supposed to disallow any communications? If I try to start Bluetooth, it says it will turn Airplane mode off (as expected).
Is it a known "feature" I have missed recently?
Edit: Tested on an old 1.1.3 iPhone, it indeed warns Airplane mode will be turned off.