Local is a simple Yes/No flag to indicate if the song's artist is considered local to the station.
Local is an optional field that appears as a checkbox in the playlist entry form.
People sometimes ask why the Local flag is associated with disks rather than with artists. The answer is that artists and bands can move around or their status as local can change for other reasons. So Local should be thought of as meaning: local to the station when the disk was released.
DJs frequently point out to listeners when an artist or band is local since it is of general interest. This feature allows the fact to be shown in the online playlists.
Disabling this field has no significant negative consequences other than loss of this information and that it cannot be used as a search criterion or in report generation.