More likely 4G LTE MTM (https://www.verizon.com/business/products/internet-of-things...). It's dirt cheap and paid for by the vendor of the device it is in (usually) in the name of 'telemetry'.

I've seen so many random industrial devices and parts come into our plant that have their own cellular it's wild.

Secret 5G is not as common because there is a huge incentive to resell the free service. Maybe with eSIM it will be harder. Kindles uses to have a free data plan SIM.

My truck (Ford) has some cell connectivity that I’ve never paid for. At scale it’s likely very inexpensive.

Telcos sell off peak only 5g for cheap. Only to large companies that are willing to work with the limits. Often it is low bandwidth.

The FCC is literally powerless nowadays for all intents and purposes. They've abrogated so much of their authority to the states now that they might as well be eliminated. What little authority that remains with it is bought and paid for to the point that I'm sure you could get anything "approved" if you wanted.

> has the FCC been degraded so much that they would allow for undeclared radios in consumer products?

Well... most TVs already have a WiFi/BT chipset for stuff like advertisements or, especially with Apple, high-bandwidth video streaming. There is already a radio module present, but (IIRC) you don't have to disclose what exactly that module is capable of.