I'm doing the first bit, but I can't turn off the wifi -- only stop broadcasting my "personal" network. And actually, as I went in to make sure that was the case, I saw that broadcasting of my personal network had been forcibly turned back on. Lovely!
That is what should be illegal, for electronic devices (even if rented) to be unable to disable wireless communications, or for a contract to affect the operation of stuff other than wireless communications when the wireless is disabled. It should also be illegal to be unable to disable all power to electric devices (for devices with battery power, that would include that it must be possible to remove the battery, and the method to be documented).
If you don't broadcast your SSID, then how can device manufactures have hyper accurate location services available when GPS is not? You're not participating in the system! Hell, as much money as theGoogs gives to be the default search to various companies, would they not be willing to pay ISPs to keep that option on? I'm just throwing ideas out that I know nothing about, but I don't see why they would be opposed to the concept.
Put the thing in a faraday box.
If you cannot disable it and you don't trust the wifi but need the service, wrap the isp provided box it in aluminum foil and ground that foil ( no need to try to solder on the foil, an alligator clip is more practical), the wifi will still be on but it will be completely blind. Just make sure it doesn't overheat.