The escrow system on OB is definitely going to be the weak link. I think with any transaction involving bitcoin someone is going to have to trust someone else somewhere but that's where the opportunity is for something bad to happen. Escrow is also going to be really difficult for them to judge certain things as well (buyer says he received the item but it was a box of bricks and not a macbook etc - what do they do then?).
Same as ebay customer service does. Scanned receipts, pictures of the item, delivery tracking, etc.
Except this is where honest people can get scammed. If I sell an laptop but send a laptop box with nothing but sand in it to the exact weight of the laptop then how can anyone prove otherwise? All I can prove is I sent something that weighs the same as the laptop and the buyer signed for it. Either party can claim wrongdoing and scam whether a laptop or box of sand was sent. This is why it's not watertight and you would hope it doesn't happen but as we know from this forum scammers are rife and will do anything they can to make their money.
