For local and state police a one pass wipe probably will suffice, for FBI it probably will not. I don't think that is true about dealigning the platters or misaligning the head stack though, I know for a fact that data has been recovered from platters even after they are shattered into bits and seriously physically damaged. Does your friend not know what spin stand microscopy is? There are even more sophisticated microscope techniques for recovering data from wiped / physically damaged drives, but that by itself is adequate to pull data from shattered platters. If you are not using Secure Erase, your erase probably wasn't secure . You might want to use DBAN on top of it just incase though .