That’s a lot of overhead just to scam one guy out of the price of a used car. And the teller is almost certain to get caught and charged when the fraud is detected.
But the local police force is in on it, duh.
Most banks will swipe any ATM card and give you cash. I did that when I bought a car for $4,400 off of ebay. Call your bank and see if they will do that. No real chance of being scammed or robbed.
On that note, I had (what I assume) was a thief for a landlord one time - they cleaned out my bank account right before my rent was due by impersonating me with the teller. When I went to the bank and gave a sworn statement that it wasn’t me that took the money out of my account (and the signature didn’t match), I received all my money back. I think you’d be pretty well protected even in the cashier is in on the scam, based on my experience.
I’d also go with cash or cashier cheque that you were present to witness. And for the love of Judge Judy, get receipts signed by both parties for everything.
Cash is the most foolproof way. Anything else is risky. I got $8,000 cash for the last car I sold, it really isn’t that big of an envelope. Luckily I had my 115 pound wife with me to protect me with that much money. 
I’ve done bank to bank transfers to good effect. When purchasing a car, I’ve had the seller meet me at my credit union. The write the cashiers check directly to him, I never actually touched it.
I bought a car for $7000 on Craigslist. If the seller had insisted on cash I would have told him to find a different buyer.
I paid with a loan check ($5500) and a cashier’s check ($1500). I believe a postal money order you can only pay for in cash so that doesn’t solve the problem of getting that amount of cash (which is impossible if you’re financing the car because the financing agency won’t send you out with cash. )
Why would there be any problem ACCEPTING cash without a receipt? PAYING cash, you bet yer ass. But any vehicle sale requires some piece of paper (even just the form on the back of the title) to be filled out with a sale price, which would serve the seller for any need. I can’t imagine why the seller would be in any liability without a receipt.
Seller tells buyer: “I’ll go to the DMV first thing in the morning to get the title switched. Don’t you worry about a thing.” However, later that day, the buyer goes on a multi-state shooting/robbery spree in the car. SWAT team is dispatched to seller’s house.
Yes, your door still gets kicked in and all your possessions get destroyed in the search after which you and your family are marched to the police station in your underwear. But at least you have something for your lawyer to show the DA that you were just an innocent bystander.
You can pay for a postal money order with a debit card using a PIN too; just no method that skims a % from the post office off the top like a credit card.