In free Groupsites, all users can upload and download files to and from the Groupsite file cabinet.
There is one Basic Permission control and 1 Premium Permission control that can affect this.
Permission controls are under the MANAGER tab, then from the "Group Settings" page select Permission Controls.
Basic Permission Control
This option can make file cabinet accessibility more open and even allow non-members to down load files.
This is used by Public Groupsites that want as much access as possible.
The options are: "Anyone may download", "Only members may download" or "Default - follows Groupsite visibility".
Premium Permission Control