Diagnostic & Usage On Apple Device
Unfortunately, Apple does not officially provide any software or methods for this, so if you do take a step not advised from Apple, you are taking a risk that could affect your device or lose your warranty. That being said, I would just assume that you went to an Apple Authorised Service Provider. Having said that, you could speak to Apple Support or write an email to them on how individual stores and service providers handle devices and what information is required. I would only imagine that they would be allowed to take the Model number (for device identification) and your Serial number (for warranty status).