As for the big companies you mentioned, I think they always try to protect all possible processes, whether it's production or repairs.
Not an excuse for Apple, as they themselves published the process that would be done at a Genius Bar on their own website, they just conveniently omitted that the customer would not be allowed to see it happen & witness no data exfiltration, only firmware password removal.
Imagine thinking it's acceptable to order a drink at a bar, and god knows what happens to your drink mixed behind closed doors.
I mean now I feel like this topic got a little off topic however I really want to respond to this specifically because the internet is no longer a means of information exchange its become the new age farming tool. What are we farming you say? Well you of course an all your metadata so we can curate what your actually looking at. I mean so if i'm being the good farmer I wouldn't want no foreign entity coming an stealing my crops. When it comes to the data itself just read apple's terms of service you legit just sold yourself to them without even knowing it. I really hate the way technology has become personally anymore its not the vision Satoshi had its not a good future for our next generation and if you watch the movie idiocracy you'll be even more furious then before. Notice the shoes they wear guess what they're crocs
