Unfortunately, with every disaster comes some dishonest people who will try to take advantage of the situation. You can fully expect to see a rash of flood damaged cars being dumped into the marketplace in the near future and it is important that you protect yourself to the full extent that you can.
To this point I am going to provide a great link that I found about this topic published by the Pennsylvania Attorney General.
It is pretty comprehensive and too long to post here so I am just going to give you the link.
Let me know what you think: http://www.attorneygeneral.gov/consumers.aspx?id=1116