Even in some places in the UK their are places to buy pirated software very easily. A certain stall at the local weekly market springs to mind.
While this method will stop a lot of people it will not stop stop the real pirates. Its more aimed at the casual user thats used a mates copy who wouldn`t know where to start when it came to getting around something like that.
The problem is though they are only excluding 20 keys, their is a lot more available on the internet and i`ve seen a program before that can change the key without re-installing so it seems like that with a bit of time anyone could install SP2.