Black swan defense: Call for backup. An independent backup copy of your SaaS data, kept separate from your production cloud accounts, can allow you to recover from a cloud failure that no built-in security or disaster recovery feature can handle.
Bottom line, SaaS is new ground for lots of IT professionals and, while cloud-based applications carry some demonstrable security and data integrity advantages (notably in hardware redundancy), the cloud is still new territory for most of us. It requires new procedures and new best practices. With a little preparation and forethought, the cloud can be more versatile and adaptable than on-premise systems, but you have to adapt your security protocols to ensure your cloud benefits aren't undone by hidden security costs.