I most certainly do determine what I sync. And, yes, turning on or off iCloud photo library is one way to do that. Right now, there is a physical separation in distance between my phone and data I sync to iCloud. There is no possibility of data that I did not sync to iCloud being scanned by Apple and I am aware of all the services that sync data to iCloud. Apple wants to change that separation to be an arbitrary separation in software and the agent that does the scanning is to be located on my phone using my resources to scan data that is marked for sync to iCloud that resides on the same device along side private data that I never intend to sync with any service. Sure, it may not scan my private data as Apple has promised but the mechanism that ensures this is only code-based. The decision to what it scans in the future is outside of my control, but the tool to do will ever-present.No you don’t. iCloud Photo Library is an all or nothing service. You can switch it off, in which case the new scanning features are off as well.