A1) Your site will not be knocked offline. We use RAID1 i.e. we have two hard drives on the server which mirror each other. So if one hard drive crashes, the other hard drive takes over without any data loss. In the rare case where both hard drives crash together or some software error occurs, we can recover the entire hard drive from tape backups.
A2) We don't allow our employees to leave or enter with any floppy disks or CDs so they can't possibly carry in our out any data. Additionally, they are not allowed to access your files unless you specifically ask for assistance.