I use same Apple ID on different Macs (used by different people), only to use Find My Mac.
So I disabled Message, Facetime etc. – App Store updates are still a bit problematic since I don't want to share the account password.
We also use Drop boxes to share files, so everyone has enabled public file share of Public folder.
But since El Capitan (or Yosemite), all computers is accessible to everyone, because they connect themselves with the Apple ID (instead of connecting as Guests), and not only Public folder but also HD and Home folder are visible. (And I see the apple ID as "Connected with".)
How can I disable that?
And is there a better management of Apple IDs (I want to avoid a per-device ID)?