Yes, BrightAuthor presentations running on a player will cache a single Media RSS (MRSS) feed and retain the content files until they are refreshed.
Caching Multiple Feeds
If you are using multiple MRSS feeds with BrightAuthor version 188.8.131.52 or later, multiple feeds will be cached as long as the MRSS .xml file includes the size of the files being downloaded.
If you have several MRSS feeds in the same zone and you change from one MRSS feed to another, the first feed will not be purged so long as the sizes are included for the downloaded files.
Restricting the Pool of Cached Files
Media files that are no longer referenced by the MRSS feed(s) will remain on the storage until all available space is filled. The system will then begin removing files that are no longer referenced to make room for new MRSS content.
If you want to ensure that free space is left on the card for other purposes, BrightAuthor versions 184.108.40.206 and later allow you to define the maximum size allotted to dynamic data (MRSS feeds and Dynamic Playlists).
To specify a dynamic data pool size, navigate to Edit > Preferences > Storage and check the Limit storage space by function box. You can choose to restrict the Dynamic Data pool by either absolute size (MB) or by percentage of the total storage. When this pool is filled with cached MRSS files, the system will begin deleting files that are no longer referenced by the MRSS feed(s).