Is this just a theoretical thing, or have there been actual drives that lied about invalid opcodes on a read and then proceeded to destroy the drive if you issued a fallback read? I have a hard time believing a hard drive would behave like a C compiler if I'm being honest...
As I mentioned earlier, there was a series of CDROM drives that upon receiving an unsupported command (and this was before you could discover it) would lead to all further data being interpreted as firmware data for an update and brick the device. If you issued a fallback read then the device would become bricked, if you reset the bus and reinitialized the device, everything was fine.
Discovery has of course improved this, so we know what a harddrive can and cannot do. Harddrives that lie about what they support shouldn't have the appropriate seals and trademarks of SATA or SAS on them, as they must be certified by those entities.
