Domains changing owners and parking

I have a question,lets say person X own some domain and park it at NameDrive, then that some1 sells this domain to person Y, and then person Y also put this domain for parking at NameDrive.
While person X hasn't deleted this domain from his NameDrive portfolio, so the question is will he still get money for it even if he doesn't own the domain any more? will they both be getting the money for the same domain?
I mean they both has this domain in their portfolios, and the domains DNS are NameDrive's, so how NameDrive can know who is the real owner?  ???

I've had this happen to me when I pick up dropped names...here's what I did:

I added it to my account at Sedo (where it was parked before I bought it) and then it told me Sedo needed to verify the name. After about 3 days, I decided to email Sedo about the situation. I told them to send an email to the address listed in the new WHOIS record to verify that I was indeed the new owner.

You'll probably have to do that as well!

The problem you describe is depended on the web application that the registrar has for domain parkings.

In my opinion this would be a very very sillly bug and should be fixed, so if you think that the money from the domain you own goes to the previous owner you should contact the company, and if they don't give you a good answer, maybe you should tell them that you will take legal actions, etc....