RE, I've learned that one as well. "How are you?" will get an honest answer from a difficult child, usually filled with information NFME (not for mom's ears).
You reminded me of another one...
You know you're a warrior mom when you have perfected the art of the content-free conversation.
difficult child: "Hi Mom. Where's Dad?"
Me: "He's gone out."
difficult child: "Oh. Where did he go?"
Me: "Oh, he went out." Said with the vocal intonation as if I'm naming a specific place where husband has gone.
difficult child: "Oh, okay."
(This is to head off at the pass the inevitable Where did he go? when did he leave? When's he coming back? conversational gambits that ensue. difficult child is a MUCH more social aspie than I am, so I've learned that as long as the words have the veneer of conversation, content is irrelevant.)