>but it's probably not enough to persuade other people that it's gone.

I believe there is a long standing bounty for anyone who can retrieve useful data from a drive that had been zero'd once. No one has been able to thus far.

A lot of the disk wiping "culture" stems from a much earlier time when disk technology was less reliable, especially in regards to writes. Dan Gutmann himself says that the Gutmann method is long antiquated and only worked with MFM/RLL encoded disks from the 80s and early 90s.

Perhaps instead of humoring these people, we should be educating them. A zero'd out disk is a wiped disk until someone proves otherwise.