On a PC help site, in response to a question of what would fully erase a HD, someone came up with this when I raised the question of just partitioning to erase the HD.
You can, But all it does is wipes the partition table and writes a new one. The HDD still has most of the data on it, The HDD has just flagged all the sectors as being empty - were in fact they still have the data there. It is only gone once the HDD has written over it. When you delete something, where it is located on the HDD its just flagged and the computer says its empty. But its actualy still there, untill written over by other data.
Now, when I've used WBtoolbox, and have partitioned a HD, it warns you that by doing so, everything will be erased. Does AOS handle it differently than on the PC side?