Why should the device share its connection with you?
As to the cost, one of the main selling points of 5G networks is their suitability for large-scale low-bandwidth uses (IoT), usage tracking among them. Samsung and others will be able to collect data from millions of devices at a very modest cost. Ericsson etc expect billions of new devices on 5G networks in the next five years. Networks are being designed for a minimum of one million devices per square km (0.39 sq mi), what do you think they will be?
We've already seen built-in connectivity. Some Amazon Kindles used to have free Amazon-provided 3G connection that worked in most of North America, Europe and other more developed parts of the world. It's only a matter of time before it becomes universal.
Samsung is launching their first 5G-enabled TV this year. 5G is there for 8K over-the-air streaming service, but can (and I am certain that will) be used for tracking purposes too, even if not subscribed to anything. The hardware is there and the cost is minimal - so why not?
