OK, this is applicable to several different devices, but since my specific context is an AppleWatch, figured I'd just post it here. 
The scenario: you purchased a used AW that has an, existing, AC+ agreement, that was paid up front (i.e., it's not monthly). The AC+ is not transferred to you as the new owner (why it didn't occur isn't really important ...). Let's say the AC+ runs out in a couple of months - now, as the current owner of the device, after the original AC+ expires (in the original owners name/account), would be current owner be able to startup month-to-month AC+.
I'm assuming if AC+ __was__ transferred, that would [almost assuredly] be the case, but I'm wondering about the above scenario. Again: used device, a few months AC+ remaining, stays in the original owners name/account, can the new owner go month-to-month after it expires (or even before it expires for that matter).
The scenario: you purchased a used AW that has an, existing, AC+ agreement, that was paid up front (i.e., it's not monthly). The AC+ is not transferred to you as the new owner (why it didn't occur isn't really important ...). Let's say the AC+ runs out in a couple of months - now, as the current owner of the device, after the original AC+ expires (in the original owners name/account), would be current owner be able to startup month-to-month AC+.
I'm assuming if AC+ __was__ transferred, that would [almost assuredly] be the case, but I'm wondering about the above scenario. Again: used device, a few months AC+ remaining, stays in the original owners name/account, can the new owner go month-to-month after it expires (or even before it expires for that matter).