This should be a required option, even if it's opt out. The consumer should be able to turn off this kind of remote authorisation over their device, even if it reduces the "herd immunity".
Killing core functionality goes a step beyond IMEI blacklisting, which can be circumvented by selling the phone outside the blacklisted jurisdictions. An IMEI-blacklisted phone is a phone with a reduced market. An effectively "killed" phone is worth its recycling rebate.