To be fair, it's a lot easier to harden the equipment they own vs the equipment your customers own. I'm not sure such a cipher icon is even possible in iOS without Apple's help. It certainly wouldn't be easy.
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...
