I dont think it matters, and I don't think eBay are bothered about anything than making money, their opinion is that if someone gets stung..tough.. though they still take the fee's including a percentage of the postage if payment is recieved via paypal.
Examples.
I got negative feedback from a seller I didnt recieve goods from, I had contact thru ebay in my ebay, showing he still had items I paid for, and him saying he had them, and I had evidence of him asking for more money.
Now I won multiple items, which I had bid on after him agreeing to combine postage, and send all discs in the same package 1st class, it took weeks for me to recieve a couple of discs in bin bags.
I recieved a single positive from him for the promp payment, but after waiting for discs (the rest never arrived, and he had stated in an email that he still had them), I complained.
I recieved a negative feedback for an item I had clear evidence of paying for, eBAy did nothing about it even after months of complaining, they told me to sort it out with the selller, who got away with selling me shoddy goods, stealing money off me, and giving me negative feedback.
I was selling an expensive road bike, it didnt sell, and I had to relist, but ran into difficulties as the bike had been previously sold by me according to eBay. Turned out someone had sent invoices to bidders of the first listing, and again on the second listing, the winner of the second listing was getting invoices from two sources. eBay left me and the potential buyer to sort this out amongst ourselves, we found out the details of the fraudster and I ended up selling my bike.