Ah, wedding etiquette!!!! I think the "new etiquette" is "It's our day and whatever we want goes." Sad to say, but I go to most weddings with low expectations anymore.
Sorry to hear about your situation, Marleybone. I'd go the making other plans route.
When we were out of town guests at two of my nephews' weddings, but not in the wedding party, my sister made sure that we were included in the rehearsal dinner.
But the pictures the next day at both of the receptions were another story. I'm not sure who gave the photographer's assistant the list of family members, but we weren't on it. The father of the groom's family was, but not us, the family of the mother of the groom. (And it isn't like the groom's parents are divorced or anything.) At the first wedding, I saw the assistant gathering people for photos and assumed that our turn would come eventually and didn't really think about it. Afterwards I realized that we'd been overlooked. At the next wedding, I made sure to make ourselves known to the photographer, but he wasn't too sure about it as we weren't on "the list".
Neither of these nephews and their wives bothered to send my daughter even a card when she graduated from high school last year, or thank you notes for the homemade knit stocking ornaments that I made for them last Christmas!!!!
The son of a good friend is getting married in May and she appears to be practicing pasting a smile on her face and zipping her lips. The invitation came a couple of weeks ago and is almost tacky. Either they did them themselves on the computer, or the printer did a shoddy job. Plus there isn't an inner envelope and the reply card is a postcard. Now that I can understand from a postage point of view, but the printing is cockeyed. She would never say anything, but I think she is mortified. She is the type to do things the prim, proper and old-fashioned way.