Unlike the Read-only attribute for a file, the Read-only attribute for
a folder is typically ignored by Windows, Windows components and
accessories, and other programs. For example, you can delete, rename,
and change a folder with the Read-only attribute by using Windows
The Read-only and System attributes is only used by Windows Explorer
to determine whether the folder is a special folder, such as a system
folder that has its view customized by Windows (for example, My
Documents, Favorites, Fonts, Downloaded Program Files), or a folder
that you customized by using the Customize tab of the folder's
Properties dialog box. As a result, Windows Explorer does not allow
you to view or change the Read-only or System attributes of folders.
When a folder has the Read-Only attribute set it causes Explorer to
request the Desktop.ini of that folder to see if any special folder
settings need to be set.
This is an old article but it is still true for all versions of Windows.
To prevent the creation of files in a folder, change the permissions using the
Security tab in the folder properties. Click the
Advanced button and add a rule to deny access to
Create Files / Write Data.