It's been a while since I went down this rabbithole, but I think it is required via spec, but only if your SIM card has that feature enabled ... and no carriers

It's been a while since I went down this rabbithole, but I think it is required via spec, but only if your SIM card has that feature enabled ... and no carriers anywhere (globally) enable that feature. So I would be interested to see what happens if you insert a SIM card with security checking turned on, into an iphone...