Ok, so this one is a little strange, and I'm hoping you guys can help me navigate it.
So some backstory:
A friend of mine from a few years back got engaged a few months before me, and had been really open and share-y with her plans on Facebook (so I knew where she was at with planning, even though we rarely talk). When I got engaged, she offered to meet me for lunch, since she had "lots of great cost-saving advice!" she wanted to share with me, so I thought, sure, why not. In our discussion she talked about how she has already sent out email save the dates (I hadn't gotten one, which was completely expected) and that she would be saving tons of money by sending email invites as wells. Not my style, but ok, good advice for a budget bride. Then she started talking about how she is going to be inviting 1,000+ people to the ceremony, in an attempt to fill the church, but that only around 100 or so will be invited to the reception. I asked, "isn't that a little rude to all the people that you're inviting to the ceremony that know you are doing something after that they aren't invited to?" and her response was something like "the ceremony is the important part, they should just be supportive of us saying our vows and understand that we are on a budget for the reception." This was before I'd ever come on TK and learned terms like "tiered wedding" and "B-listing."
I was a bit aghast at that idea (a reverse-tier?) but thought nothing of it, as I hadn't received a STD and she made no mention to me that I would invited one way or the other. Also, we aren't really close at all (except geographically) so she wasn't someone I would have considered inviting to mine, either.
So fast forward a few months later, and my fiance and I both get email invitations. On the invitation it even said something to the affect of "we are very sorry that we are not able to accommodate everyone at our reception, this invitation is just for the ceremony, thanks." So I WAS one of those "lucky" people who was so special enough to receive an invite! Anyway, Fi and I both declined, because we already had plans on the day, not to mention the rudeness factor. Also, there wasn't a registry, but there was a note that said "if you'd like to send us money, here is a paypal link" and then a long description of where they want to go for their honeymoon... kind of implying that they wanted cash for their trip. I personally dislike giving cash, but will do it if the couple is polite about it. But when they ask? No way.
Then a few weeks ago, out of the BLUE, we got a wedding gift from them. They aren't invited to our wedding, but she still looked up my registries and sent us something. I sent a nice thank you card and wished them all the best with their upcoming wedding... but do I need to do anything else? I read on here once that someone said "it is in poor taste to accept a gift from someone not invited to your wedding" but what should I have done? It was shipped directly to my house, so it's not like I could "refuse" it in person. I have a feeling that it's her way of guilting me for 1) not attending her wedding but also 2) for not contributing a cash gift to them. I want to believe it was just a nice gesture but it's very... strange.
Is there any etiquette rule that says I need to reciprocate and give them a gift? The last thing I want to do is be rude, but there's nothing worse than feeling forced to give a gift.
TL;DR: Non-invited guest invited me to part of her wedding, which I declined for legitimate reasons, and then sent me a gift, do I need to send a gift now?