OK I'll bite.
What are your favorite comeback lines to be delivered to stupid or disapproving strangers out in public?
I have a few which range from he very abstract:
"It's OK. He's half Scottish"
(confuse them and run)
to the sublime.
"Please don't touch her! She has a rare skin condition!" (I.e. SID) -Getting well-meaning strangers to keep their hands off my very cute but very tactile defensive DD is a HUGE challenge. Of course, I am just waiting for the day when she tells somebody at school that she has a rare skin condition. That one could bite me in the behind real hard, real fast! LOL.
We printed up some t-shirts for the kids with slogans such as "I have Autism. What's your excuse?" but never really wore them last year, when summer passed us by. This year we will.
I otfen challenge a strangers qualificaions: "Are you a psychologist?" ("/expert in early childhood development"/etc), which usually works.
I happen to have a very scary stare and a scary-looking DH with an even nastier stare, so that usually stops all but the least faint of heart.
One problem I face is controlling Peter; who may take a dislike to man with a loud voice or to a mom who corrected her child in his hearing. he will often chase after him/her, growling and shouting (sometimes swinging).
In those circumstances, I usually have to ask the astonished stranger their first name, while holding back my snarling son. Once I know their name, I can introduce Peter to them and he desists. Most people in those circumstances recognise immediately that the child is non-standard and just tell me their name without question.