Katie, they may have changed on how/if they want to create a case for stolen hardware.
A few systems ago, it was possible to mark an item stolen in the system with a plain tick. That hasn't been possible for some years now.
But an Apple authorized service provider (and support of course) can see what cases or repairs were previously associated with a serial number. So if a Mac owner called to the support to ask advice e.g. about iTunes or browsing, if the same Mac of which the serial was used in association to those cases on the call is later taken to be repaired, they can (or at least previously could) see the headlines of the support cases. If there were cases that seemed directly related ("Lots of applications crash randomly" as a title for a recent case and then unit comes in for that repair) it will be helpful for them to have a look on what that case was about, for instance.
On the same way, if a computer was reported stolen to the support, and a case was created with the title of something like "Stolen laptop" that should be clear enough for the service provider to call in for more info, and then to proceed accordingly.
I guess if the system or procedures preventing logging the cases for lost items was changed again, that could be for preventing wrong serials being reported, or for worrying the systems might not get up to date info if the Mac was later returned to the original owner.
But, the more places the serial is able to be found, associated with its history of being stolen, the better. Usually I wouldn't recommend posting a serial number in the net (or at least hide part of it: ab123XXXyyy if it was for other purporses, as it can still tell the model, configuration, and when it was built even if the xxx (in that location) are covered. But in this case I don't see how even the full serial number, even in this particular thread, would do no harm. Maybe someone who is about to buy it, or has it, or someone who is asked to do some repair on it, would then find the history of it being stolen.
- that makes me wonder: would it make sense to make a pinned thread for all the computers and other Mac gear reported stolen by macosx.com users in the classifieds section?