Oops, My Bad!

I do not have a poker face, people tell me they can read me like a book. What do you think this face says?

Let me tell you the story behind it because I'd really like to hear your comments.

Recently I went to UT for my niece's wedding. My daughter, Amanda, and I were helping my sister set up for the reception. We set the guest book outside on this little table they had and we decided to sign it right then and there. Immediately afterward, I mean like we had just capped the pen, this lady (a friend of the groom's family) came up to us and gasped.

(Gasp) "You just signed the front page! Didn't you know you aren't supposed to sign the front page of a wedding album when it's a picture album, too?"

I gave her the "Are you trying to pull my leg?" face and just stared at her. "Are you kidding me?"

"No. Most brides put a post it note on the front page asking people not to sign there."

Let me show you again the look I gave her...the "Oops, My Bad!" face:

To that she gave me a conciliatory pat on the arm, "I'm sure it's OK. The bride didn't put anything on there so I'm sure it'll be just fine." And then she walked away.

Um, yeah, I'm sure it'll HAVE to be fine since we've already done it. Plus I'm her aunt so there's no escaping me. And we asked other ignorant family members to sign with us so we wouldn't be the only ones on there for long. Ha ha, I know I say Being Happy is Better Than Being Smart but I don't want to look like the only dumb one! 

But that makes me ask: Am I ignorant about that? I've been to many wedding receptions, even had one for my own daughter(!), so why am I just now hearing about this? When did this become a THING or was she just trying to pull a fast one on me?

BHiBTBS but I don't want to be behind the times. Fill me in people!