You are totally wrong.The guy was okay to record this conversation inside his own vehicle, if he had set the recording up inside the dealership somewhere it would be a different story.
Recording in the dealership would be OK since it is a "public area", I can't think of more private place than a car with shut doors. This has nothing to do with "what" belongs to "who" (most likely the car belongs to a bank anyhow) - it has to do with a reasonable expectation of privacy.
As far as nanny cams go - they are expressly prohibited from recording audio.
But than again, you're certainly entitled to your opinion, even if it's wrong.
Source: http://www.citmedialaw.org/legal-guide/recording-phone-calls-and-conversationsRegardless of whether state or federal law governs the situation, it is almost always illegal to record a phone call or private conversation to which you are not a party, do not have consent from at least one party, and could not naturally overhear. In addition, federal and many state laws do not permit you to surreptitiously place a bug or recording device on a person or telephone, in a home, office or restaurant to secretly record a conversation between two people who have not consented.