Yeah, I've heard more than one or two horror stories about parents and inlaws at weddings. But I think when at uni I heard how the brides parents wanted to dictate the dance music (they brought in older barn dance style music) and a few other parts and when I asked why I heard, "we are paying for it" I made the decision then and there. There would be only 1 person organising my wedding, me! I will also pay for it and it doesn't matter how big or small I can afford it and HB can take as much of a role as he wants, but inlaws are out.
Roll forward 10 years and we both get on with each sides inlaws fairly well, but I stuck with. I organised everything and just advised. My mother intially expecting to be asked to do alot was a bit surprised when she ask about something, I just said its done (even if not). Finally two weeks prior the parents couldn't stand it and phoned up and advised us they were paying for the reception and alcohol so don't argue. I didn't argue. Grand also paid for the wedding cake. Mum later thanked me for leaving her out and praising my efforts. She felt some of her friends were the my mum did this for me so I'll do for my daughter, but time has moved on.
Not one person was at our wedding I didn't know or either of us personally didn't want. I read on another forum about not wearing too low a cut dress as you could be dancing with your mum's or dad's boss. Not a chance, my wedding, my dress and I'll show off my boobs and I'll dance with I god damn like. I'm not some puppett or brain dead woman doing as she is told. Today is about me, organised by me because of me and paid for by me and not forgetting the man of the hour either. My gran asked about what type of dress I was wearing, I put on the table a few conservative ideas (not really intending to go through with any). She said ohh know, you cannot wear that you have such a beautiful figure, wear something he won't forget and you won't regret later in life when you look back. A few weeks later I showed her my dress and she gave me thumbs up and said very sexey dear. Mum also gave her approval but I would have worn it anyway.
So my feeling is to deal with either side, plan it yourself, leave them out and advise them what to do on the day. If they dont' go along, relegate them to the back rows. A friend of my threatened that her divorced parents couldn't be civil for 8hr for her neither would be invited to the wedding or do see their grandchildren. This was after they argued on who they would sit with. It worked and they sat next to each other at the parents table with new spouses on outside of the pair. They even agreed to do the parents dance together before their new spouses could cut in.
On my night I danced with only a hand ful of people, my HB, his best man, my dad, my new father in law and my brother. A few others asked by I refused or said later saying I was with talking to people, which I was.
In end my wedding was great, what I and HB wanted and lots of people kept talking about our wedding years later and after the last drink was drunk, I owed no money to anyone. I cannot believe people borrow money for a wedding.