I can't imagine that a car dealership would even care, as long as they got to sell a car.
"Oh dang, you ticked the 'not a robot' box but you are actually a robot ... Ah, no worries, I'll put a call in to head office, get the paperwork changed. Well, enjoy your car! ... And don't forget to come back in six months for your free oil change! ... for the car, I mean."
Hm, so selling to a robot without someone behind to represent would be extralegal I guess, and if any problems occur during the trade you'd be on your own?
The closest thing would probably trades with wild animals. Are there any laws on that? (Probably not, but the situation is not unthinkable.)
I wonder if in the far future we'll have two androids pretending to be human and trying to fool each other at the same time, only for them to realize that they are both, in fact, robots
The twist at the end is that she's lying.