So apparently my FMIL made a faux pas and did the give everyone an envelope so they can fill in their address for me.
I had no idea, or I would've told her not to. It's not like I don't already have everyone's address (how would i be able to send out their wedding invites!) She is also under the impression that every female invited to the wedding should have been invited to my shower too. That one is NBD though.
Boo to the envelopes. But I guess I'll have to use them anyway, it was nice of her to get me thank you cards.