How old is he again?

DS is just 2 and can't speak and a few days ago I took him to McDonalds to have a play because it had been raining for a few days.
I never thought anything of it until this post. A few girls about 3-4 years old, took DS under their wing and literately treated him like a baby. Simply because he doesn't listen when I tell him to do or not to do something and because he doesn't talk. So they kept saying things like "Baby needs a bottle. Baby needs to come here so he can go and sleep in his cot. Baby needs food. Baby needs this that etc."
DS just went along because he loves hanging around other kids, yet thinking back it is quite hurtful. And yes, lucky he doesn't comprehend yet.
DS is only just 2 and started speech about 5 months ago. He'll join the Early Intervention program next year and Im praying hard that his speech will eventually pick up/kick in. I would hate to think kids treating him like a baby as he gets older, simply because he cant speak.
By the way, have you looked into Makaton for him? You dont need to use all the signs, just the most important ones. You might be able to get some communication going that way.

As for the t-shirts, as long as its not an "I am autistic" and therefore labeling themselves, than it' a good idea. The shirts at the website mentioned by a PP, are really good. Alternatively, if you want something cheaper, you can always get something made with a local printer shop or even Big W does t-shirt printing these days I think.