Found the answer myself (more details [here][1]). Basically, it's as simple as setting the Group Policy called `Monitor file and program activity on your computer` to **Disabled**.

For users of Windows editions without *gpedit.msc*, a DWORD entry called `DisableOnAccessProtection` must be created under `HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Defender\Real-Time Protection` and set to **1**.

The name of this registry entry tells you exactly what "Monitor file and program activity" actually do: It scans files "On Access" (such as when Windows Explorer lists the contents of a directory). Nothing more.


  [1]: http://superuser.com/a/1090888/358758