This actually happened: one day a colleague and I were taking a shuttle bus from the airport to a conference on Lifelike Computer Characters. We had a demo the next day, and were still having software problems. We were so deeply immersed in a conversation about our dysfunctional animated demo character that we hardly noticed the two women who shared the shuttle bus with us, listening with rapt attention.
My colleague and I ran down the list of problems the character was having balancing properly, reaching for things, and tracking the position of moving objects with his gaze. The two women were nodding silently, completely absorbed in our discussion. Then my colleague mentioned one persistent problem with our demo character: Under certain conditions his head would pop off and float in the air about two head lengths above his body.
As he said this, both of the women seemed to jump in their seats, looking completely startled and alarmed. Then they just sat there, obviously very upset, and stared at the two of us as though we were both out of our minds. We stared back, and there were a few moments of uncomfortable silence.
Finally I asked “are you here for the conference on lifelike computer characters?”
The women looked at each other and laughed, obviously immensely relieved. “No,” one of them said, “we’re here for the conference on child autism.”