OK, you're a carrier and have millions of Apple and Samsung devices on your network. 0.01% of your users know how to update the OS on their Samsung phones themselves, or jailbreak their iPhones. A software update from the manufacturer could brick millions of those phones on you network.

Which risk keeps you awake at night:

  A few Samsung phone users bricking their phones occasionally
  A few iPhone users bricking their phones occasionally
  50 million Galaxy phones being bricked by Samsung at once
  50 million iPhones being bricked by Apple at once

I'm not saying it's impossible Apple could do it, but in terms of ratios how much more or less likely is it versus Samsung?