This came up in conversation with a group of friends, and I haven't been able to find a consistent answer anywhere!
A friend of mine was given a plus one to a wedding where she would not know any of the other guests aside from the bride and groom. She is not dating, and would like to bring her brother as her wedding "date". However, she wasn't sure whether it was frowned upon etiquette-wise to bring a sibling as your plus one.
I couldn't see why it would be a problem, but others weren't so sure. I thought I'd bring it to you fine, etiquette experts. Would it be a faux-pas for her to bring her brother to this wedding?