I don't see how that letting you know the ebay ID of the person who gave you the free snipes is a breach of privacy.
They could even have a 'check this box to let the recipient know who sent the free snipes' question so that they'll know that you'll know!
This is an annoyance - I try to refer lost of people but, apart from the 3 snipes appearing, you have no way of knowing if they've registered...