Not vehicle related but my Dad is a National Trust volunteer and in the house where he works there is a collection of Ming type ancient Chinese pottery. He says he's lost count of the number of people who've asked, in all seriousness, whether they are dishwasher-proof!
He also reminded me of the anecdote relating to the brash American tourist at the Bodlean library who asks whether the building is pre-war? The curator replies "Madam, it's pre-America!"