If a dealership wanted me to log on to my banking website and show them my account information, I would have laughed in their face as a walked out of the building. Better yet, when they do something like this, ask them to show you the last 20 deals they made and the profit off of each. They won't be as easy with the disclosure process.
I don't care if they were giving me the car for cost!

I bought a car in April. I had financing already set up through my Credit Union, had a check for the dealer & everything. Before I could do anything, I had to log onto my banks website to show the salesman my checking account balance! I felt extremely violated, if my bank felt I was worth the risk, to give me a check for the car, why did the dealer need to see down my blouse (so to speak)? Why aren't they at least running the checks through that check verifying place? *sigh*

In my opinion, the sales people in the industry of cars, motorcycles, ATVs, etc. are so desperate for "the sale" that they are blind to the red flags. Get the sale and deal with the repercussions later.