When Bears second daughters wedding approached I tried for over a month to find out what her Mother would be wearing. I kept asking and everyone seemed to brush it off as "I dunno. Wear what you want. What's the big deal?"
I insisted o knowing and finally got "Her dress is blue, I think."
Following the ceremony Gail came up and gave me a hug and said "Well, don't we have great taste?" I didn't get what she meant at first but then... Yep, exact same dress! I was so embarrassed! But, she laughed it off and said not to worry about it. She knew I'd been asking and hadn't bought it until a few days before, so how could I have known?
Grandma always said that one is not to wear the same dress as the bride, bridesmaids, mothers of the bride / groom, the Queen or the First Lady. Other than that, you assume YOU bought your first and the other person should have checked with you.