I recently had a rather impassioned discussion with Apple's gurus, regarding second-hand devices and the previous device owners NOT preparing their devices for sale or another user to log into.
I was shocked and dismayed to discover that the bottom-line from Apple is this: Without the original user's Apple Id and password, the device should be not used but rather thrown away; disposed of.
The first thing to note is...
DO NOT BUY A SECOND-HAND APPLE DEVICE WITHOUT CHECKING IT IS USABLE BEFORE YOU LEAVE THE SHOP!
A great many 2nd-hand shops do not know that the previous user's credentials need to be removed by the previous owner themselves BEFORE resale and wind up selling an unusable device to the public, who then bring it to me to fix, which can't be done even with proof of legitimate ownership!
In conclusion, I would advise people abstain from Apple devices for this reason. Apple purport that the feature is to protect people's data, yet a firmware reset doesn't remove this same data as is expected.
The final thing to not is that Apple advised me to not accept 2nd-hand devices for repair, which leads me to this conclusion...
Buying an Apple device is a binding contract to Apple and their philosophy of technology, which some may love, but being bound to it is hard to love about anything.
The fact that people are not being advised on how to remove their associated account from the phone BEFORE selling suggests Apple is not informing their customer base about the lifespan AFTER it's usefulness has expired with the previous owner, exacerbating the issue even more.
Out of interest, if you're looking to sell your Apple device, I have found an article on how to remove your associated Apple Id from the device PRIOR to selling.
A huge number of iPhones and iPads have had to be put to waste, thrown away simply because they can't be used again by a different user, resulting in a huge contribution to electronics waste to environmental pollution - These devices contain harmful elements which endanger life.
In summary, although Apple seem to have garnered a few die-hard fans of their philosophy and aesthetic, it still remains that many aspects of Apple's practices are putting people's noses out of joint, making it harder to get on and ultimately rendering electronic devices as waste products. I would've advised against purchasing Apple products based purely on their fenced-in approach to usability, but this is the final nail in the coffin as far as responsible device producers are concerned.