Apple's "unit of measure" is AppleID accounts. Apple doesn't want "devices" blocked because they change hands often. As much as device theft and such is bad, it's preventing another paying App Store customer from buying stuff. Apple benefits slightly from people that make 12 different accounts in these cases. It would also lead to problems with malcontents locking people out of apps and device IDs that weren't their own. The headaches to Apple of devs using Device IDs are bigger than one or two companies problems.Since you'll be entering personal account data anyway to register, this seems like a perfectly reasonable need for device registration as well.
Apple should come up with an API where an app writer can simply ask the mothership if this device has been registered in such a way before, and another call to tag it thusly when it is registered.
Create a solution, instead of leaving a real and costly problem in place.