On the subject of serial numbers, the ones for your hardware and peripherals are also being transmitted as "telemetry", which gives them even more options to spying on you, ex:
1. If your printer has tracking dots [0] then a printed flyer can be tracked back to your computer, IP, and MS/Apple account.
2. If a device is reported on two computers, MS/Apple know there is some kind of connection between the computers.
Is there any reason to think that the government couldn't force Apple to hand over the same data? They may or may not have taken over entire rooms at Apple (https://en.wikipedia.org/wiki/Room_641A) but you can bet they've at least got devices sitting on their network collecting data.
1. If your printer has tracking dots [0] then a printed flyer can be tracked back to your computer, IP, and MS/Apple account.
2. If a device is reported on two computers, MS/Apple know there is some kind of connection between the computers.
[0] https://www.eff.org/pages/list-printers-which-do-or-do-not-d...