The invite says "John/Jane Doe and Guest" for people who are dating someone right now or for people who the bride and groom don't know for sure if they are dating someone right now. Then the bride and groom made a personal phone call to everyone telling them if their invite says "and Guest" they can only bring someone they are dating if they are dating them at this moment. If they break up with that person between now and the wedding, they can't bring anyone else. And if they are not dating anyone right now, they can not bring anyone.
I was caught off guard by this and little unimpressed with it. I follow it because it's their wedding and their money but it just feels kind of choosey.