I don't have any properly scandalous ones which is surprising as I'm Irish and I've probably been to 30 or 40 big chaotic weddings.
There was once an odd scenario where a wedding guest wore a full length white lace fishtaiil dress. It was made more confusing by the fact she was similar in appearance to the bride - who didn't seem bothered at all.
Another time I went to my cousin's wedding and was introduced to his friends, all presumably single based on their interest in me and the other cousins. In the bar one fairly handsome charming guy and I hit it off, I gave him my phone number and agreed to a dinner date. My other cousin (best man) appeared, sat down and glared at him till he departed. I was confused and even more so when a very timid looking young woman appeared and sat down looking at me forlornly. My cousin snapped "he's not here". Without a word she stood up and walked off smiling apologetically at me. She was of course his wife. All very odd.
I asked my cousin about it and he was filling me in that the guy is blatant in his bad behaviour and the wife just calmly accepts it's, it's really sad. I was shocked and hanging on his every word. Myself and this cousin are very close and we ended up roaring laughing as we kept talking about various other stuff.
Imagine my surprise when I turned to find yet another silent woman seated at our table but this one looked furious. She stared at us both, me then him then me again. Finally she spoke "so who is this?" My cousin shook his head and told her to get a grip explaining how we were related. She turned out to be the sister of someone he had recently dated.
I couldn't help it, I started to laugh. This made her absolutely incandescent. Before I knew it herself and three of her mates were hurling abuse at me, I was flirting with their friends husband, I was flirting with my own cousin, I was disgusting.
I decided it was time for bed and fled.
The next morning at breakfast it was smiles and hellos all round like it never happened.