That is funny, but if not driven during the winter - specifically on salt-covered roads (and having lived in NH - holy hell do they LOVE their road salt), it could have a certain level of truth. When I first started dating my ex-, she had a 1997 BMW M3 and had owned it for about 5 years. However, she had only lived in a house with a garage for about a year. the other 4 years, the car lived outside. However, she had a second car so she never drove the M3 once there was a hint of snow or salt on the roads. When I started doing maintenance and repairs to the car in 2002, the underside was pristine. Every nut and bolt came off easily. Especially for a 5-year-old car living in the rust belt. So, where a car lives or even how it's stored is less important than how it is used.
Of course, that doesn't mean I would trust this ad... thorough inspection required.