My fiance and I recently sent out links to our family and friends to gather their addresses for STDs and invitations. One of my step cousins, whom I have talked to maybe twice in my entire life, added a guest through her link. Actually, I didn't even send her the link; my step aunt did because I don't have her contact information (we're not friends on social media and I don't have her number).
I thought it was extremely rude of her to assume that she can bring a plus one, given our barely exist relationship. I asked around the family and learned that this person is a guy she recently started seeing. My mom and my step dad want me to invite the entire family, to which I agreed because they're helping us paying for part of the weeding. However, I am not comfortable inviting a total stranger. We're having a small-ish wedding around 100 people, and we want everyone we love and care to be there; people who are going to be truly happy for us, not some random dates you find on tinder.
Our rule on wedding guests is quite simple, you have to know at least one of us to be invited. We've been together for more than 3 years and I have met most of my fiance's friends and family and their significant others, and vice versa. So we actually know the majority of our wedding guests pretty well, and I look forward to meet the ones I never had a chance to meet before the wedding.
In the case of my step cousin, we will still send her an invitation but it's going to be addressed just to her. I am not judging people's relationship by the length, as it doesn't matter to me whether they have been together for two weeks or two years. But it is our wedding, and your relationship to me and/or my fiance matters. If you couldn't bother to congratulate us on our engagement, you don't deserve a plus one at our wedding.
I know it's against wedding etiquette, but I would like to hear what you think on this issue. Thank you.