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I know a way that worked for a friend of mine.

He bought Apple Care on ebay, but instead of registering online (which would not have worked after 1 year) he called up Apple Care and told them that he bought the Applecare with the computer and didn't realize he was supposed to register it. He just gave them the code and serial number and they registered it for him.

Not saying it would work, but it did for him.

If you buy Applecare at an Apple Store or at Apple.com, you are signed up as soon as you check out. So, in theory it could never happen there.
 
Not possible in reality, in luck maybe, you would have to reach the dumbest applecare associate in the world, as if you buy applecare with the computer for the last five years at least, it is automatically registered, and the representatives know it, that rep probably does not have a job anymore if that was true.

Not really, it only gets automatically registered if you buy direct from Apple. There are plenty of places that still sell you a box with an Applecare code inside that you have to register yourself.

A lot of the time people would forget (or the store might forget to tell them), and Apple, being a company that likes to assume positive intent, will just register it for you.

If it doesn't work, you can always sell the code on ebay again, so all you lose is the selling fee.
 
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