Proof of successful completion of the data erasure is provided through a certificate of data destruction that is generated once the device is successfully wiped.
2) ONSITE HARD DISK DRILLING
Drilling a hole in the drive enclosure which passes through all the platters will make it impossible to run the drive. Most modern HDDs don’t have air inside the enclosure, and you’ve let what was in there escape. You’ve filled the cavity with tiny pieces of drill swarf, which will be on everything including the platters, and will crash the heads if someone tries to lower them onto the rotating platters. You’ve also unbalanced the platters, though I don’t have an estimate for whether this will be fatal. The drill bit will likely pass through the controller board on the way, which though not fatal will certainly not help anyone trying to hook the drive up.