I bought my BMW outside of ebay after going to view it.
The seller even gave me the £20 back that I had saved him in selling fees.
If people send money for a car they haven't even seen especially through insecure means such as bank tranfer then they only got themselves to blame if they get scammed.
I think they are going to get themselves into trouble charging people if they think a sale was completed outside of ebay.
Unless they have 100% proof then people are going to refuse to pay the fee, or take ebay to the small claims court to recover the fee. And without 100% proof then ebay are going to loose the case.