We got married on Sunday and it was beautiful (pictures to come), but I was opening some presents before the wedding and we got several things from our registry from someone who was not a guest. H and I have no idea who this person is, and neither do our parents. I'm not sure if someone accidentally ordered from our registry instead of someone else's or if a guest couldn't figure out the online registry and had a friend or neighbor order something for them. What should I do about these gifts and a thank you note?