Hi DG,
If you let me know the domain, then I can let you know which account it was in. To give you an idea of how much traffic we have hitting our DNS which is not in listed in an ND account, we set up something a month ago to catch any names which were unlisted but hitting our DNS as a 'service' so that if people were losing revenue from non-listed names, we could simply transfer it over. Sounds easy. Within 24 hours, we had 10,000 which should have been listed in that account. Among them google.com, aol.com etc. We have a vast amount of stuff hitting our DNS which is not listed in accounts, so we immediately disabled this.
We wanted to do this as we had some people who were forwarding domains without adding it to their accounts and were losing out on 100s of USD, so we wanted to make sure that we were able to successfully track the traffic and put the stats in their account. Obviously, sending out 10K notification emails on a daily basis isn't really possible.
In any situation like this though, we will always transfer stats over to the rightful owner if we have any stats to go by.
Hope this clears it up a bit.
Ed