There's an option in the security section, about making public reports visible to outside users... is this refering to users not in the application that recieves reports by mail?
The olap schema caching feature saves the cube schema which improves the performance. On the other hand, the cube schema can get out of synch with the report definition.
A report can be marked public. When "Make public reports visible to outside users" option is enabled public reports will be visible to unauthenticated users.