Fun experiment, but it isn't as much of a gotcha as people here think. They could have verbally tricked a human customer service agent into promising them the car for $1 in the same way but the end result would be the same – the agent (whether human or bot) doesn't have the authority to make that promise so you are walking away with nothing. I doubt the company is sweating because of this hack.
Now if Chevrolet hooks their actual sales process to an LLM and has it sign contracts on their behalf... that'll be a sight to behold.
To add, it's not just about who has authority or not. If you try to trick someone, even if the person you tricked has some kind of authority, a contract signed based on this trick (i.e., fraud) can likely be voidable.
Now if Chevrolet hooks their actual sales process to an LLM and has it sign contracts on their behalf... that'll be a sight to behold.