Thanks indigo, for your kind words and suggestions. I spend about 96% of DS' waking time with him, so I've become somewhat attuned to him.
I really like your suggestion about simple one-word responses. All this time, I've been focusing on how to have DS communicate effectively, but I failed to appreciate the very real communication barrier between DS and his age-mates. It's no wonder he gets so frustrated at the impasse. That suggestion is more attention-getting.
The other day, a parent actually laughed and commented on "how cute" DS was when he cried and said, "I need more space." Call me a stodgy old stick, but I said, "He's not being cute, he's afraid and is trying to protect himself." I think most parents who hear him self-advocate almost don't believe what they're hearing and get caught up in a did-he-just-say-that loop. Ugh!!! Try listening and respecting his request, parents!
ITA about not prejudging others' children or touching them. How children behave at a given point in time is influenced by so many factors to which I'm not privvy, so I try to assume the best. One of the little boys was being a genuinely friendly, if somewhat clingy, natural extrovert.
I will use my body as a passive barrier between another child and DS, but I actively avoid touching the other child for exactly the reasons you mention, even if only a gentle redirecting pat on the elbow is needed. I'd prefer not to do this wherever possible because I think it sends a subtle message to DS that he needs to be protected from other children.
