IT people automatically know what data needs to be backed up even though they were told there was nothing important on the drive.

This happens quite a bit. You get tasked to reimage a users computer and you make sure to specifically ask if there is anything the user needs off of the computer because the reimage will wipe all data from the hard disk. Erased. Not there anymore.

Then, after the reimage..."Where is that file?"

And of course it is your fault.