Pay with CASH. Do they require Social Sec Number?

[zmyride]

I want to purchase this used car which i want to use for daily commute. I can't drive my Z in stop-and-go traffic everyday, it's not fuel efficient car.

So the dealer and I agreed for $12500 out the door. I went to the bank and get a cashier's check for that amount. Then the dealer made me fill out the application with my social security no. I refused and walked away.

Is it the law to require you to fill out your ssn eventhough you pay with a cashier's check. Even my bank didn't care. I have nothing to hide but the Fed can track me thru my cashier's check, why do they care about my SSN.

The only time i give out my SSN is when I finance the car, which in this case, i'm not.