[_-david-_]

>Apple's new system only scans photos you attempt to upload to their cloud.

And what if in the future they decide they need to scan more than images going to the cloud? What if there is some huge epidemic of child abuse or some other terrible thing and Apple decides they need to do more?

Once you open Pandora's Box you can't close it.

[GeekyBear]

What if in the future Google starts selling your location data to anyone willing to write them a check?

Once you open the Pandora's Box of collecting location data, you can't close it.

[grupthink]

Both will happen. Basically, Apple is able to scan data on your phone, and Google is able to scan data on their servers.