That's a good point, and then there are of course back-ups to be considered. Deleting data is surprisingly hard, but fortunately for path this is 'bulk' so that makes it a little bit easier.
Making sure you really lose a single record is a lot more expensive because then you have to selectively remove it from your spinning back-ups as well, in this case you can just wipe the back-ups of the file by opening the file for 'update' and overwriting it with random data.
http://www.networkworld.com/news/2011/042511-google-hard-dri...