I Now Pronounce You Embarrassed and Unrecognized

This weekend my mom was visiting the East Coast. She flew into Philadelphia to see my brother, see Amish country, shop The Christmas Tree Shops, but mostly she was here to attend the wedding of one of her best friend's daughters.
After work on Friday, I drove up to Connecticut from New York to meet my brother and mom at the hotel near the location of the wedding. My brother and I have always been confused why we're invited to the events of our mom's friends, mostly because we don't know any of their "kids" as well as I think their parents wished we did. While all the kids are lovely and accommodating, we're sure they don't want us at their weddings either.
My parents, brother and I were all born in the same town in Connecticut. My mom's best friends and their children were also born in that same town. The difference between us and them is that they've lived there their entire lives, while my family (with sister added in West Springfield, Mass.) has moved seven times removed from our roots.
Last summer we went to another one of these functions, meeting many people we didn't think we'd see again.
Well.
In order to be helpful, my brother and I went over to the wedding site early and set up where we could, as there was another wedding wrapping up minutes before the next was to begin. There was nothing for us to do except not look forward to the next five hours of our lives.
With arms crossed, we talked away the time and eventually people started to show up. A guy walked up to us and said, "Hey, I think I met you at another one of these things last year."
I said, "Oh, yeah, [mom's friend's daughter's] wedding ..."
Then my brother says, "Who are you again?"
"I'm the groom."
Ouch.
"I'm going to leave you guys alone now."
Wow.
The best part, outside of the WORST kind of embarrassment, was his best man snickering in the back at my brother's mistake. To be fair, I was seconds away from asking this guy the same question, but saw that he was wearing a tuxedo. Thank you, context clues.
After shot-gunning a few drinks to ease the tension, my brother and I ran into another wedding guest: the son of one of my mom's best friends. He walked right up to my brother, shook his hand and said, "[Brother], how's it goin'?" I extended my hand and said, "Hey! How have you been?" The amount of dead space in the gaze returned my way could only be explained by Carl Sagan. He had absolutely no idea who I was. Meanwhile, a few feet away from the awkward exchange was a photo collage including a picture of us STANDING WITHIN INCHES OF EACH OTHER. (Ok, the picture was taken when I was four years old, in a kiddie pool, also known as the first and last time I wore a bikini. Whatever.)
Suffice to say, my mother assured us we would never have to attend another event of people we didn't know, and who clearly did not know us.