I am increasingly buying IoT aka smart devices for my household.
All these devices need to be connected to WLAN and proprietary app (via bluetooth on iPhone). I do this initial step, but then block the internet access for the IoT device in OpenWrt router.
I can then control the device on the local network via app on iPhone, but hopefully avoid the device calling home and providing personal data to the manufacturer.
My iPhone has an internet connection and a Bluetooth connection to the IoT device.
Could the device theoretically send personal data to the manufacturer via iPhone/Bluetooth? Is this done in practice? Are there any manufacturers that are able to outsmart a blocked internet connection?