So far, Canon USA has always covered these models that come with a USA warranty card. Just send in the card to establish the date of purchase. If asked for a invoice, it was a Christmas gift, which is why you registered it.
If its a gray market unit, you might have a issue, but I doubt it.
With Canon tightening up things via their MAP program, they might stop fixing gray market from unauthorized sellers, but I don't expect them to stop fixing units with a USA warranty card.