The ban is based on a german regulation that outlaws devices with a hidden listening/recording functionality. The fact that the devices are often insecure and allow arbitrary persons to listen in is a secondary issue, the primary issue is that the children (and people around the children) cannot determine that the device has a recording/transmitting function and even if they know cannot determine if the device is currently transmitting. The rights of the persons around the children exist and need to be enforced, so the devices in their current form are illegal to sell or to own. Seems not so odd to me.
That functionality is outlawed, and the official statement explicitly only talks about watches having it. The article pulls all kinds of "connected devices" concerns into it that don't apply to the specific decision.
The article is wrong on that account. Children smartwatches are in general allowed, just not models that have monitoring capabilities. GPS tracking for example would be legal.
They are not banned for being insecure IoT devices, they are banned for being hidden listening devices. the IoT angle is something that's just in the BBC article and the statements of their experts, not in the ban notice.
The advise about 'destroying' watches you have is a bit odd too. Why not just return them or remove the listening in capability with a firmware update?
This is a legal thing: they decided that merely owning one of the affected devices is illegal. So the best way back to legality is to destroy the device and keep a proof of its destruction. Nice and tidy.
A firmware based fix alone does not make the device easily distinguishable from one without it and the fix is not permanent, making it possible to revert the device into its illegal state.
Cell phones don't generally support for non-present parties to enable listening in as a feature and if they did, they'd be banned under that regulation as well.
What? Yes they do. In fact, that's the original purpose of the "phone" part.
I spent 5 seconds searching and found dozens of apps that allow you to remotely enable the microphone on a cell phone (granted, you have to install the app first, though that can also be done remotely).
The original purpose of my cell phone is that a present party can either actively initiate or accept a call, allowing a remote party to hear their words. None of these actions is hidden or disguised or can usually be enabled without my consent. Installing a software that would allow a non-present party to initiate a hidden listening connection would be illegal. Yes, such apps are available, just as the smart watches now banned were available.
Note that devices that are obviously and primarily made for recording or transmission are not affected, microphones, video cameras etc. are not illegal.