Anyone who thinks that "reformatting a filesystem" is the same thing as "wiping a hard drive" doesn't understand the meanings of the words "reformatting", "wiping", or "filesystem' for that matter.

You can reformat an ext*, FAT or NTFS filesystem, but if you think you've "wiped" the filesystem, much less the drive, you are wrong beyond description.  I can understand a non-technical user not understanding the distinction between "reformatting' and "wiping", but anyone working for a corporate IT department who can't tell them apart should be fired for incompetence.

If I'm asked to "wipe" someone's drive, I'll boot to a live CD or USB drive, get to a root prompt, and do something like

export pass=1
while [ $pass -lt 6 ]
 do
  printf '\nDrive Wipe Pass #%d' $pass
  dd if=/dev/random of=/dev/hda
  printf ' . '
  dd if=/dev/zero of=/dev/hda
  printf ' . '
 pass=`expr $pass + 1`
done; printf '\nDONE.  You may now turn off the computer'

This is not a theoretical exercise for me.  I had a customer who was retiring, and wanted to be sure all data was removed from the server before it was delivered to the buyer.  Since it was SCO OpenServer, instead of /dev/random, I used an outer loop of 3 passes with an inner loop that used /dev/byte/55, /dev/byte/ff, /dev/byte/aa, and /dev/byte/00 (after first creating the device nodes for 55 and aa), so that the entire HD was written to a dozen times, with the different patterns.  At that point, I figured that there were maybe some guys at Langley (and their Russian and Chinese counterparts) who would have even a chance of recovering data from that drive.

I never referred to that operation as "(re)formatting".