You're quite right, while malware is a threat often the biggest issues come from...

You're quite right, while malware is a threat often the biggest issues come from unforeseen bugs. Users with a long memory may remember the iTunes 2 update fiasco. where Apple's own update script was responsible for wiping user data.

The below link explained the error, and how it only occurred on certain volumes: http://www.xlr8yourmac.com/OSX/itunes2_erased_drives.html