"rpm -e" removes the package from the database even if the package files can not be removed due to e.g. read-only file systems. Without enforcement (--force) it should print out the error messages and not touch the database. To ensure a consistent system rpm must prove (e.g. by touching the package files), that all files are removable before it removes a package.
You need to add you RO files systems to rpm configuration, something like mkdir -p /etc/rpm echp "%_netsharedpath /path/to/fs/1:/path/to/fs/2" >> /etc/rpm/macros