Imo, the "easily detectable" thing isn't true. That's damage control. Or theory as far as possible countermeasures go. They can't ban all devices running a blank unregistered dev-id in general, and then unlink the ids owned by legitimate testers and users. That's hopeless.
If the backup solution is what I think it is, then it also doesn't need to use a particular ID, nor can that program necessarily broadcast it's ID just like that.
So in the short term, Sony would probably use a more simple solution, basically involving a dual track for firmware updates. Where the retail ps3s get one kind - disabling a number of IDs from use. Possibly needing to be specifically unlocked for bought software (again, not a complete solution). While "testing" firmwares wouldn't have that blacklist.
...anyway, personally, I don't care, as long as Sony is up in arms and flailing around like flight-less chickens. Maybe they'll end up having to invalidate all their dev-kits, and send out renewed certificates for any new game released. It's going to be hilariously expensive for them either way. And it's certainly not going to stop me from pirating any first-party Sony titles in the future.. that is, if I have any interest in playing them.