Interloper in Business Class.
We were spending our kids' inheritance by flying in Business Class, on boarding we found a young lady in one of our seats. I checked our boarding card and we were correct, as I went to query her, the flight attendant asked her for her boarding card, this showed her seat was back in economy! I was wondering if the seat hadn't been allocated could she have got away with it? Also, would the airline have taken any further action?