I strongly object to “(eg, consider a relatively common use case of a USB key with encryption keys on it; all snaps with removable-media auto-connected would have access to these keys).” in the auto-connection request considerations.
I’d like to see data to support the assertion that USB keys commonly contain encryption keys. I think there’s a certain class of user who does this. That’s not nearly as widespread as the guide suggests. Anecdotally I have around 50 USB keys around my house and none of them have or have ever contained encryption keys. I’d argue the vast majority of users use USB keys to contain data, photos, videos and documents.
I will at your request raise this outside the forum though.