I have a couple stories.
My "father" is an abusive fuck head who more than once held a gun to my mothers head in front of me. So, imagine my feelings on the subject of him coming to my wedding. In addition, most of my family on that side are pretty fucking crazy in their own right, defending him, hiding him from the law, etc... When I got married, I did invite my aunts, uncles, and grandmother. Basically, I think I have been MORE than reasonable and understanding to the whole "he's your son/brother" thing.
BOTH of my aunts showed up in white mother of the bride type dresses. My grandmother insisted on coming into the bridal dressing room, (in a CHURCH) and giving me a bachelorette present to open. It was a sex kit, vibrator, lube, the whole 9. In addition, they told my father about the wedding. Luckily, he was arrested (he was a deadbeat, just happened to be pulled over for a traffic stop and the warrant was found) just 5 miles from my wedding. These people live 2 states away. I haven't seen any of them since the wedding, 15 years ago.
The other wedding was my cousin.
They got married in June, a HOT HOT day. Heat index in the triple digits. My aunt made everyone (including my 98 year old grandfather) stay outside of the church until she was ready because SHE wanted to "receive" everyone as they came into the church. Then, we all had to wait in a hot church through the wedding, get into cars, drive downtown, walk around in that heat, and get into the reception. None of that is unreasonable, until we got to the reception and the crazy bitch did the same thing. My husband and I actually snuck around the back and let my grandfather in out of the heat. He needed some water, no one would allow him to have it because my aunt (mother of the groom) had left orders that no one could drink until everyone was seated, the bartender ended up giving us one of his bottles of water and told us not to tell anyone. After an hour, there weren't enough seats for everyone, no food was being served, so we all left and went to Ihop and took my grandfather home after. We're not talking about a poor family either, these people were relations by my mother's 2nd marriage. I was the only grandchild (and I'm not blood) who was more concerned about the well being of a 98 year old grandfather and 81 year old grandmother than the appearance of everyone having the same glasses and shit.