One of the moms next to me started talking about how mature her daughter, who was sitting next to my daughter, was and how her older sister is so advanced that she started reading in kindergarten (she has no idea my clown of a child started reading at two) and I think the hidden message was "my daughter can't relate to rowdy children beneathe her intellectual development" and maybe she is right one some level,I know some of the really bright kids on here were the quiet ones that liked more mature games, but she has no idea what is actually hidden behind all that noise...or maybe they do because every once in awhile they might hear something come out of her mouth that gives her away, but I get the feeling no one would think a kid who acts like that is bright.
My DD is typically very quiet in group situations and I often think that others can't tell that she's smart. (Personally, I'm glad that others can't tell, but I do wish that DD wasn't so intimidated by large groups.) Maybe this mother is having the same insecurities that you are--thinking that everyone is assuming that her kid isn't bright because of the way that she is acting. I wouldn't assume that there was a message of superiority there; and, in fact, to the extent that there might have been, you should keep in mind that people often communicate superiority when they feel inferiority.
It sounds like your DD was the life of the party. Be proud of her great social skills, not embarrassed that others couldn't see her intellectual gifts as well.
