Set time and date without passcode?

Most of you are probably aware of the bug (iOS 6-) that requires you to set the correct time/date and than restart the phone after a disconnected battery, either by setting it manually or connecting to wifi.

I run a small iPhone-repair shop and because of this bug I have to ask every single customer for their passcode or spend time teaching them how to resolve the issue themselves.

This, of course, is a real annoyance that Apple should have solved a long time ago, but that's not the point of my thread...

I got to thinking... is there any way to solve this issue without the customers passcode?

I mean, of course it's impossible to access the wifi or time settings without the code, but is there really no other way of correcting the time/date? iTunes? 3:rd party software?

Any ideas?