The link that Jon references above does seem to state that only the specific computer that created the boot disk can use that boot disk.
Assuming that I'm following you, Jon's linked doc states that
If you're using the Recovery Disk Assistant, you can only use the external recovery drive with the computer that created it.
but an external recovery drive is no more than a free-standing
Recovery Partition (disk)...not the same as an
installer, boot, as you've called it, disc. (As I recall, there was much confusion about that when Recovery Disk Assistant was introduced.)
So it is no surprise that each System is now specific to some extent to a particular computer.
That's always been the case, although perhaps not to as great a degree as now, but the limitation applied to install discs and was mitigated by the existence of retail discs.
Whatever we users may gain or lose because of it notwithstanding, Apple has apparently used its new OS X distribution scheme as an anti-piracy measure. (I wonder whether eleemosynary or proprietary interests drove the change?
)
Edit: I recall reading something about new motherboards necessitating burning in of their serial numbers...Virtual 1, maybe?
