The majority of developer time is never spent on writing code for a feature, but testing it. The costs for this feature would be testing it on previous devices, like making sure the hit region was large enough, that it couldn't be activated by palms, ensuring that there were no bugs in the specific encoding hardware on each model that were triggered while switching capture config with a live viewfinder, etc.
It's non-defaulted. A screen pops up and forces you to choose an option before you can use the phone. This was actually covered in previous articles on the beta, so a dramatic bold statement assuming Apple did the wrong thing is totally unnecessary.
