Women's are really crazy and think from their kitchen experience only. Cars have so expensive multilayer of paint to live for so many year. To protect that paint it has few coats of lacquer so that paint wont get burnt in sun in a year or two.
Every layer of lacquer you scrape off, will leave your car shiny like new, but after few months or year all the paint will get faded spots by sun burning, as no lacquer protection layer is present. In your case vinegar might kill the lacquer layer and leave your car paint without any protection.
Bottom line, don't use vinegar on car and leave that crazy housewives idea in the kitchen for few hundred dirhams cutlery and crockery. Professional grade car shampoo have strong cleaner to fight the dirty spots but gentle enough to not to scrape the lacquer off. My two cents.