iPhone Service without passcode?

I guess they need to run some diagnostics, but still it's somewhat odd. Wiping the device clean is one option, but like you said, it's a bit overkill for a short operation. One compromise could be to switch to a temporary passcode for the service and then switch back to your real one.

But I do wish iOS supported multiple user accounts, so you could create a separate account for repair purposes.

 

I would never hand my iPhone with all my data and passcode to anyone. Do a encrypted backup, reset the phone like it came from the factory before taking it to Apple. You can restore it afterwards.

 

Do a encrypted iTunes backup and wipe the phone, before going to the Genius Bar. Very simple and no more privacy concerns.

Which is more important, getting your phone repaired, or not wanting to do a iTunes restore, because you don't want to be inconvenienced?

 

Running diagnostics as another person wrote. They started asking recently. But if you have a recent iOS they don’t need your passcode anymore 10.3 I think.