Clueless in Minisink

This afternoon I attempted to take all four of my children to my nephews swim meet. I figured that this would be a good environment for Walker since it shouldn't be too loud and was indoors. Unfortunately, i forgot all about the acoustics and how magnified everything sounds in the pool area. Needless to say he wasn't too thrilled and I ended up walking with him out in the hall while the other three stayed inside with their aunt. My sister noted that as a woman was walking by Sawyer and saw her sitting quietly she commented "now that's a good baby" It amazes me how clueless and judgmental people are! Although society is becoming more aware of children with autism and other disabilities they still have no clue! Because my son doesn't show any apparent issues, he was looked at as being bad??? I think it would be asking a lot to have any child, be quiet and content at school functions. Isn't the school one area that should accept all children? Where families of all types should feel comfortable?
Should he have to wear a sign stating "loud noises bug me out"? or do we just keep him home?