I realize we have dozens of thank you note question posts in the past, but I really did not see my particular question asked; I apologize! I believe I am likely to encounter a similar situation with my future wedding thank you notes, as we are planning to have a registry with Amazon.
The main label on a gift I received was signed from my adult cousin. However, when I opened the gift, I noticed that my aunt's name was on the packing slip which was taped to the gift, not her own. My best guess is that, as my aunt is usually responsible for previous gifts, she allowed my cousin to choose and use her account to order the gift, but I can't say I know. They do not live together. Do you think I should send separate "thank you" notes to both, or just let it go and send it to my cousin? In this instance I doubt they'll chop off my head as they do not send thank you notes for normal gifts, but I at least want to know the etiquette if this occurs with future wedding gifts.