For certain notions of "read/write", the risk can be lower. You might make backups to storage, but not have permission to delete files. Or when you delete files

For certain notions of "read/write", the risk can be lower. You might make backups to storage, but not have permission to delete files. Or when you delete files, they are kept for a certain safety window (e.g. if you delete a file on June 24, the file is instead moved and can be restored any time before July 24, at which point it is purged).