Apparently you are a very advanced user. 99% time users want, explicitly or implicitly (more often, and they get sad or mad if their implication is failed) you

Apparently you are a very advanced user. 99% time users want, explicitly or implicitly (more often, and they get sad or mad if their implication is failed) you to return their devices with all their files intact. So the technician needs access to dump their files and put them back in after re-installing the OS. Advanced users just backup and wipe their data themselves before they handle the computer to the service.