Nevím sice, zda jsem odborník nebo ne, ale stačí si přečíst ten odkaz, kde je:
Registry: Writes outside the package - Allowed if the user has permissions. Writes under HKLM\Software are allowed as long as a corresponding key/value does not exist in the package hive and the user has the correct access permissions.
Soubory: Writes outside the package - Allowed if the user has permissions. A write to C:\Windows\System32\foo.dll is allowed if the package does not contain C:\Program Files\WindowsApps\package_name\VFS\SystemX86\foo.dll and the user has permissions.