I had a similar experience two weeks ago. They asked for my iPhone's passcode when I went in to have my screen replaced. This was apparently going to be stored in a database — I saw the form field on his iPad.

When I refused to give it to them, on the basis of privacy, the employee said that Apple could not provide the service. He backed down a little when I asked to speak to his supervisor, but then said that not providing my passcode would void my iPhone's warranty. Eventually they performed the service without my passcode and had me perform the functional testing myself before walking out of the store.

I wonder how many thousands (millions?) of iPhone passcodes are stored in Apple's database? And of course the average owner probably doesn't think to change the passcode after the service is completed.

The reason for asking for your passcode is so they can perform functional testing, and they don't end up giving customers a device that isn't perfect.

It is stored in a database, but the passcode is deleted immediately after the genius marks the service as completed.

"Deleted immediately" is more likely a flag in the database being set to "don't show".

Well, it might be deleted immediately from the prod DB, but there is always a DB backup...

For computers I create an unprivileged "apple" account when it goes in to service. For iOS devices I just wipe them before service, but if you are sending to a third party repair house you might make a new throw away account, otherwise your device is in a stealable state.

I suppose if your device is beyond being able to operate then you are going to need to change your password or passcode when you get it back.

Refuse. Tell them you have a backup and are willing to risk having to reinstall everything. That's worked every time I've had service done there.

It's probably just a standard question so Apple can migrate your data if the repair fails and you need a new machine.

My MacBook Pro battery had to be replaced too and the Apple rep asked the same thing. I just told them I rather have them wipe the machine instead and they were happy to just put that in the service notes.

That is odd indeed. I had the opposite experience a few years ago when I had a broken iPhone. I tried to give my account (iCloud) password but the clerk (Genius) stopped me and said "No, just the phone PIN so we can unlock it."