Cheers for the history lesson, it's good to know the full reasoning behind things.
However if the automated feature would use the same function of "disk zero spares", then surely running in manually has the same inherent risk involved? There's always going to be edge issues (like disk shelves blowing up due to a firmware update), but hopefully that shouldn't stop development? OnTap 6 was 4-5 years ago now?
Along with what Andrew said, I often find customers with un-zeroed spares that they had no idea about. Maybe a disk replacement wasn't zeroed at factory, or perhaps a maintenance recovery didn't zero the disk, but maybe 1 in 3 customers I see have this. Perhaps this is because the majority of customers I see are because they need some guidance, but it is quite a high number.
Or perhaps just an AutoSupport or log message that prompts that their are non-zeroed disks in the system? Similar to when you have un-assigned disks in the system (although this is only on boot).