If page secure/errors.jsp are display for user (e.g. Re-index, Restore from backup), announcement banner is hidden.
It's better (if announcement banner have set "public") display one if is possible.

Announcement banner is good place for feed-back to user. E.g.: "I'm sorry. Server is down because ... Please call hot line on .....".
I known, Data for Announcement are store in database. If I Restore from backup aren't available.

May be it's reason for create "Error Announcement banner" and store this in property file.

Thanks for your comments.

Cheers,
Libor