How does Recovery partition download eligibility work?

Hi there, I've been doing some searching on the subject but still don't have a clear understanding.

I have an older Macbook Pro that came with 10.5, and currently runs 10.8 that I bought from the Mac App Store and installed. While I was doing a clean install earlier, it asked me to log-in with my AppleID to make sure I had purchased 10.8. So the license appears to be tied to my ID rather than hardware.

If I had been using a new Mac that came with 10.8 from the factory, and I didn't have to purchase it from Mac App store, would that license be tied to the hardware and thus not ask the user for his AppleID?
I've seen videos where the recovery installer didn't ask for AppleID, and began to download OS X right away.
Is the recovery installer checking the computer serial number with Apple servers to verify if that computer shipped with 10.8?

Thanks.

Thank you, that's a great technical description in that link.

But my ultimate question remains, a mac that shipped with 10.7 or 10.8 will not require an AppleID verification when restoring the same version?