Exactly what have they got, if you never connect it to a network afterward, either? A key-log that never makes it back to them?
(I’m presuming here that the laptop is openable, and that you will do so and physically remove any wi-fi M.2 card from it — and associated antennae — since you won’t be using it. There might be some sort of extra surface-mount snooper chip left onboard that could replicate the same function — but without big antennas, how’s it going to report?)
You might not understand the depth to which you can be exploited. They will simply let you use your laptop and switch your USB cable, which has a built in 6ft antenna.
(I’m presuming here that the laptop is openable, and that you will do so and physically remove any wi-fi M.2 card from it — and associated antennae — since you won’t be using it. There might be some sort of extra surface-mount snooper chip left onboard that could replicate the same function — but without big antennas, how’s it going to report?)