Teachers? Neighbors? People in the store? Family?
We are doing about the same: close family members, close friends, people involved in his treatment/education. We want him to live-up to his fullest potential and not become 'labeled.' We also don't want people treating him different. He already has low self-esteem, so being called names or labeled won't help in our opinion.
We tell everyone now mostly because I do not let what others think bother me. I have found in the last few years that when you tell people they identify with Autism. Most say they have a friend or relative that has autism and it sparks up a conversation. I do use it sometimes as well to educate the ignorant because if you get those people looking at you funny and who are bold enough to say something stupid I generally say loud enough fir all to hear my children are autistic. Most of the times others that do understand give the ignorant person dirty looks.
I don't expect people to treat our children differently because of their autism I just want people to know what it looks like and why my children act the way they do sometimes. We go to some of the same stores that our children actually enjoy going to and in each of them are cashiers that know us now but at the beginning didn't. When we told them the children were autistic they all did not know what it was at first but some of them actually looked into it and have since had conversations with us and the children because of it. Now if someone else in line gives a dirty look or makes a comment these people will say something and we don't have to. We are always asked how the children are doing and if everything is ok. So when I am asked if we hide it I always say no and I never will.
I share his diagnosis with family, close friends, and anyone involved in his treatment/education. To anyone else, I say, "He's got his own way of doing things."
Ive never had a problem telling anyone that my son is on the spectrum... its just a part of who he is.