Physically, even people with access to Microsoft's data centers must get formal permission each time they visit the center. Microsoft's products and services that utilize the cloud are built to be very fault tolerant and robust. Businesses that are considering the move are encouraged to try out Microsoft Office365 to try out a free trial, to get a feel for the type of resilience that Microsoft provides.
One of the chief concerns of any business considering the use of cloud services is security and resilience. By using a global network of secure data centers which conform to strict international standards, Microsoft is able to provide peace of mind to businesses making the move to the cloud.